Did I miss the initial massive resistance to the T's joining the LGB movement ?

Yes, you clearly did. Amongst lesbians in the US and elsewhere, there was massive resistance to the Ts joining starting in the 70s, when AGP men first started pushing to be let into lesbian spaces and to be considered lesbians themselves. Look at the controversy that happened over letting a TIM be part of Olivia Records in the early 70s. And look at what happened to Michfest. Look also at the work and personal experience of lesbian feminists who very loudly and publicly sounded the alarm about the Ts such as Janice Raymond, who published "The Transsexual Empire" in 1979, Mary Daly, Sheila Jeffreys, and Cathy Brennan.

Amongst gay men too there was strong resistance to letting the Ts, even the homosexual ones, play a major role in gay rights. During the AIDS crisis of the 80s, there were lots of gay guys who expressed disdain and even revulsion for their transvestite brothers. Guys who did drag were seen as one thing, guys who lived as transvestites were seen as entirely another.

I know quite a number of gay men who were active in gay rights in the 70s and involved in groups like ACT UP during the AIDS crisis of the 80s who felt embarrassed by and even contemptuous of gay transvestites and did not want to align themselves with them - they saw TVs as "other" and as bad for the movement, on par with the gay pedophiles of NAMBLA and PIE.

After the documentary "Paris Is Burning" came out in the early 90s, many of these men said their eyes and hearts were opened a bit, and they began reassessing their revulsion and rejecting attitudes towards these other men. However, many of these gay men still were adamant that giving transvestites "a place at the table" was "problematic" for gay rights for a number of reasons.