They stopped the testing in the mid-90s because an unexpectedly large number of athletes competing as females in elite level international competition turned out to have XY chromosomes - and many of them & their countries lodged complaints of discrimination. The complaints first alleged discrimination based on sex & sex characteristics, but over time the complaints involved allegations of discrimination based on race, ethnicity and geographic place of origin.

When mandatory sex chromosome testing of athletes competing in the female category was instituted in 1967, it was widely assumed that athletes found to be XY would be automatically withdrawn from or declared ineligible for female competition and would just bow out. This is what happened when women's world champion alpine skier Erika/Erik Schinegger of Austria was found to be XY with a DSD shortly before the 1968 winter Olympics where Schinegger was favored to sweep all the women's events, and handily too: https://youtu.be/8mgQ97TKxc8

But this started to change as more & more XY DSD athletes & the nations they competed for lodged complaints. The watershed event was the case of Spanish hurdler Maria José Martinez-Patino, whom the IAAF deemed ineligible for competition in female sports in 1986 after sex chromosome testing showed Martinez-Patino to be XY. In court, Martinez-Patino argued that as someone with AIS (though which kind - CAIS, PAIS or MAIS - has never been made clear) she has no male athletic advantages - and also that mandatory sex testing constituted a severe violation of the privacy, bodily integrity & human rights of all women in athletics & especially of persons with DSDs. José Martínez-Patiño won in court and was cleared to try out for the 1992 Olympics, but didn't compete coz she fell short of the qualifying time in the trials.

After that, the IAAF & IOC reviewed their policies, and in the mid 1990s both decided to abandon mandatory sex chromosome testing for female athletes once and for all. AFAIK, no XX athletes were consulted or even considered in these decisions - the sole concern of the men who revoked the old policies was to placate & be fair to XY DSD athletes. AFAIK, no XX athletes ever lodged complaints about the sex chromosome testing. And why would they? After all, it involved a simple cheek swab that took a couple of seconds & caused no pain or indignity - and it only had to be done once in an athlete's entire career. Compared to the standard drug testing that all athletes go through which involves dropping trou & urinating in full view of sports officials, the buccal swab sex chromosome testing was nothing.

BTW, Martinez-Patino went on to serve on the 20-person IOC subcommittee that in late 2015 decided that trans-identified males with intact genitals should be allowed to compete in women's Olympic events so long as for 12 months beforehand they lower their current circulating testosterone to a level 5-10 times greater than the typical female level. Of the 19 other people on that subcommittee, 14 were "regular" XY males, one was a trans-identified XY male, and only four were XX females.

Since the loopholes to allow XY DSD athletes into elite level female sports started to open, certain countries, particularly poorer and non-white ones in "the Global South" such as Kenya appear to have actively looked for XY DSD youth with athletic potential & scouted them for the purpose of having them compete - and win - in international women's sports. (Since XY DSDs are associated with consanguinity, it's easy for national authorities to know what regions of their own lands to look in.) As a result, whilst XY DSDs are quite rare in the general population of the world, the IAAF/WA reported in 2015 that testing of athletes showed that in elite women's sports XY DSDs are far, far more prevalent:

46 XY DSD in our athletic population is approximately 7 per 1000, which is 140 times higher than expected in the general population.

https://pubmed.ncbi.nlm.nih.gov/25137421/

In the current century, a huge international PR campaign has been conducted to support the inclusion of all XY DSD athletes in female sports, even those with fully functioning testes & male-typical sensitivity to T who've gone through male puberty, which how we ended up with three such athletes - Caster Semenya, Margaret Wambui & Francine Niyonsaba - winning all three medals in the women's 800m at the 2016 Rio Olympics. In this campaign, and the associated court cases, most of the arguments employed come straight from the playbooks of queer theory, critical race theory and decolonization.

These arguments challenge the standard biological definition of what constitutes a woman - and more. The backers of Semenya and other XY athletes with similar DSDs say the issue of defining & differentiating human sex is far from settled. They also claim that what biologists say about sex as well as the cultural & medical views of what constitutes a woman plus science itself are oppressively racist, Eurocentric, colonialist and heteronormative. Further, those who take the side of Semenya and other XY athletes with DSDs similar to Semenya's have appropriated feminist arguments, saying that subjecting athletes competing in female sports to sex testing is "policing women's bodies," "body shaming," and a demeaning way of measuring all the diverse women of color of the world against the narrow, heteronormative standards of "white femininity" held and promulgated by white-skinned Europeans & North Americans.

Moreover, they say the real aim of sex testing of participants in the female category of sport isn't the feminist and sporting one of protecting female-only sports & insuring fair play for female athletes. Instead, they say the real aim of sex testing is the racist one of keeping "strong black African women" and other "women of color" from "the Global South" out of elite level women's competition so that "feminine" looking white women from "the Global North" won't be shown up by darker-skinned competitors who are athletically superior. According to this reasoning, the only way pale-skinned women of 'the Global North" can be insured of winning medals is by excluding the "naturally more gifted" dark-skinned women of the "Global South" - an argument that ignores that many of the top athletes from or competing for the countries of Global North are themselves black, and that what makes "women" like Semenya, Wambui and Niyonsaba "naturally more gifted" in sports is that according to the IAAF/WA and Court of Arbitration for Sport they are biological males.

The case for the inclusion of ALL athletes who are XY DSD in female sports has been furthered by the intentional use of misleading language, and by taking advantage of the public's lack of knowledge about DSDs and most people's unwillingness ask "prying" questions or to be unkind. The media constantly calls Semenya and other XY DSD athletes with fully-functioning testes and male-typical sensitivity to T "women with hyperandrogenism," "female athletes with naturally high levels of testosterone," "female DSD athletes" and "intersex females." When, in fact, they are XY athletes with male-only DSDs whose eligibility for female sports comes from the fact that their home countries have issued them identity documents stating they are female. Tellingly, the sex of most of these athletes was not registered at or soon after birth; rather, they were issued their first birth certificates by their governments only in their teens after they'd been scouted as potentially world-class athletic prospects. For example, Semenya, who was born at home, did not get a SA birth certificate until 2007, when Semenya was 16 and already had been anointed SA's "golden girl" runner by the nation's sports authorities.