I think the use of the word "gender" to refer to the male & female sexes is justified, bc "sex" means "sexual intercourse". For instance, as far as I know, the "sexual" part of "homosexual" is actual in reference to same-sex attraction, rather than same-sex sexual attraction. But practically everyone believes it's the latter, bc of the inextricable connotation that the word "sex" has with sexual intercourse.

Most people use "sex" in a behavioral sense to mean a set of activities that can include sexual intercourse, but which are not necessarily confined to it. Oxford defines sexual intercourse as

sexual contact between individuals involving penetration, especially the insertion of a man's erect penis into a woman's vagina, typically culminating in orgasm and the ejaculation of semen.

Note that the orgasm in this definition is the one the male presumably has. Typical. But the point is: most people use "sex" to refer to a wide range of other acts in addition to PIV intercourse. These are widely known as "sex acts," which include oral sex, anal sex and phone sex. Many people think that masturbation done in solitude counts as a sex act too. Even heterosexual couples who commonly have PIV sex have other kinds of sex as well, and when heterosexual people have sex it does not always involve intercourse.

As for your comments about homosexuals, the term "same-sex attraction" does indeed mean sexual attraction. People who are homosexual are sexually attracted to other members of the same sex, just as people who are heterosexual are sexually attracted to members of the opposite sex, and bisexuals are sexually attracted to people of both sexes. Homosexual people have sex with one another, just as heterosexual people do. I don't get why you're portraying homosexuality as not being a sexual orientation that's about sex. Do you have an issue with homosexuality?

It's important that feminists don't allow transgenderism to appropriate "gender" to Trojan Horse their way into mainstream acceptance. "Gender" will always have more currency than "sex" ever will.

Why is it so "important that feminists" speak as you want us to? Maybe with you and your friends "gender" has "more currency than 'sex' ever will," LOL, but many feminists have been discussing sex, sexism and sex stereotypes for decades with no problems. We can get along fine without "gender." The word we don't want erased is "sex."