One thing that’s been lightly touched on here, but should be expanded is the impact that this ideology has on lesbians, who by definition are female homosexuals.
Planned Parenthood in Toronto ran a series of workshops called “how to overcome the cotton ceiling”. The phrase is taken from the analogy of the glass ceiling in the world of employment, where women can see the way to the top, but are blocked by invisible barriers relating to their biological sex. The cotton ceiling here refers to the cotton gusset of lesbians’ knickers and how female-attracted TIMs can best “break through” that and become intimate with lesbians.
Lesbians (the proper female type) on the other hand are not happy with this, as by definition, they are not attracted to dicks or their owners. Since year dot, it has been the ultimate male fantasy of many straight blokes to “bed” a lesbian and “turn them”. It smacks of corrective rape, used worldwide to punish lesbians for rejecting men as partners.
Magdalen Berns, the awesome youtuber, was ostracised from her university feminism group for refusing to accept such “transbians” there & in her dating pool. Her nemesis was a notoriously aggressive TRA who tried to get her thrown out of the student union.
Lesbians are being punished for having boundaries. Boundaries that are intrinsic to the meaning of their name. The clue’s in the name - homoSEXual, not homoGENDERal. The consequence is that it erases lesbian identity and existence. Women can no longer be exclusively attracted to other women, they must consider penis (if the owner identifies as a woman) or be considered hateful transphobic bigots.
Funnily the corollary of this… that gay men should consider transmen as potential partners, is totally ignored and overlooked. Men, unlike women, have always been allowed autonomy, boundaries and preference as part and parcel of their dominant position in the patriarchy.
This particular dynamic was vividly illustrated in a dramatic Twitter exchange between Owen Jones and Sarah Ditum. Owen was berating lesbians for not accepting dick, after all, the penis can of course be very much a female organ if the owner identifies as such 
. He was then asked whether he would perform cunnilingus on a transman, as obviously, by his logic, vulvas can be male if they belong to someone identifying as a man. He threw his toys out of the pram, denounced the question as disgusting and dreadfully homophobic! (My personal peak trans moment 
)
The problem is trans ideology is that we’re starting from a very much asymmetric and loaded starting grid. We haven’t got sexism, sexual discrimination and violence sorted yet… by a long chalk. To then go and map gender identity discrimination on top of that will undermine the foundations of sex based legislation and policies that we do have. Gender is not a happy sparkly spectrum of identities across a level playing field. It is a violent hierarchy, used to oppress, subjugate and punish those considered inferior and to exploit their reproductive, sexual, caring and domestic labour and to constrain them to the “home sphere” rather than having “world building/human advancement” occupations like engineering, politics or medical research. Gender reifies such hierarchical distinctions between the sexes... we should rather be levelling them, which campaigns like "Let Toys Be Toys" seek to do. Radical feminists seek to decouple people's preference in toys, clothing, ornamentation, occupation, hobbies and various other aspects of their habitus from the anatomical configuration mother nature gifted them with within their pants. Any person, of either sex, should be free to like anything, and not be considered the opposite gender for liking the things traditionally associated with that cohort.
Sex and gender and completely different things but have been conflated as it’s beneficial to male institutions to keep people in their respective boxes. I saw this comment BTL in the Guardian (which was miraculously allowed to stand) the other day, which neatly sums it up:
By eliding the difference between gender and sex, you erase the reality of female oppression, which is based on patriarchal control of reproduction.
In short gender is how women are oppressed, and sex is why.
Gender identity can be considered valid as a protected characteristic in terms of employment, housing, education and freedom from harassment etc, but crucially it must be considered completely separate from sex for the purposes of law and policy.