Oh, and I see the 'divide and conquer' thing rather differently, (as a biological realist feminist who also has left wing leanings, if those credentials add to the strength of my argument
).
As I see it, linking the trans cause with that of LGB people discredits the original group, which has made significant progress against those who discriminated against them. That progress will, of course, have annoyed those who do not approve of gay marriage and the rights of people such as lesbians to hold events without men being included. I see the TRA cause as deeply patriarchal, and this is yet another example of how that works. If the LGB Alliance is a casualty of the enforced alliance between LGB and TQIA++, well, the patriarchy won't care - they never supported gay men and lesbians anyway, and collateral damage is just that.