Personally, I'm inclined toward agreeing with this take on the matter because I'm the resident "terf" here. I don't get the phenom of gender identity, which is because I don't buy into the notion that "gender" is a real thing. In other words, I don't know what it even means to "feel female". That whole notion to me seems like a load of bullshit and the more I read about it, the more convinced I become that it is bullshit.
I freely admit to not knowing any trans-identified people offline personally and that that could very well be a factor in my persuasion. I'll also concede to being influenced by a woman I know who de-transitioned because she found gender identity to be bullshit too. And furthermore, I won't kid anyone here: personally, I find it kind of insulting that society takes such issue with cultural appropriation when it comes to everything from as serious as blackface down to matters as unserious as hairstyles and twerking, but somehow manages to find the idea of men going around claiming to actually be women and making an entire lifestyle of that totally unobjectionable and in fact offensive to criticize. Maybe I just lack the right kind of sensitivity and the fullest information that's available, but just being straightforward here about the impact of this stuff viscerally on me.
J.K. Rowling is trying to craft out a nuanced position here that recognizes gender identity, but in a way that also acknowledges the socio-political significance of biological sex. I'm not sure that's a tenable position. I don't think the transgender movement will permit her any nuance on this subject. You either have to go along with their entire program of sex-neutralizing everything, all spaces, institutions, language, everything, or you're a bigot in their eyes. Women cannot have privacy rights or be in any way sheltered from "male-bodied persons", be it in contact sports, shelters for battered women, or even in prisons as far as the transgender movement is concerned. Women's privacy and safety has to be completely sacrificed on all levels on the alter of politeness. Neither, for that matter, can anyone de-transition, or necessarily even just be lesbian (as in not sexually attracted to penises) for that matter to be in the clear with this movement. THAT belligerent attitude is why us "terfs" exist.
Were there any room, any socially acceptable space, for the J.K. Rowlings of the world to have their nuanced views, their concerns for the sex-based rights of women in addition to the safety and well-being of trans people...if women were allowed to embrace complex views like those of J.K. Rowling without being labeled "terfs" or transphobes or what have you...I don't think many feminists would continue to care about people's pronoun preferences. But that's not the world we live in, is it?
Part of the reason why there's a lack of nuance may be that LGBTQ gets lumped together, so it appears as if it's all the same. But LGBTQ doesn't work as a term like people of color does. People of color is clearly defined as non-white people who face discrimination based on their skin color, so the different groups of people within the label people of color (african-americans, hispanics etc.) share something common that applies to all of them in the same way. LGBTQ, however, lumps people together where the discrimination they face is based on sex and gender which are actually two very different things.
LGB concerns physical attraction to the same sex which is a matter of biology. In the past it was attempted to fix this with psychological treatments, but over time it became more and more apparent that homosexuality isn't a matter of psychology. The people in question weren't wrong in the head, to put it bluntly, so there was nothing to fix to begin with.
For T, however, it isn't about biology. It's about people who cannot accept themselves as the sex they were born with, so it's a psychological issue that is similar to general lack of self-respect, self-acceptance and self-love, only that it's specifically about sex because those people put a lot of stock into gender identity and don't fit the portrayed role of their sex, i.e. how either a man or woman should behave in our society. Such people can feel better after making a transition, because belief is a very strong force. But at the same time a transition may not be necessary in the first place if the belief in gender identity can be lessened, hence why psychological treatment can show positive results here. It's a subject that is a lot more complex than homosexuality and I don't think there's a single correct answer for it.
Q stands for queer as far as I know, and simply describes anything else that isn't LGBT, but seems related.
In any case, more distinction should be helpful. And as a final note, transpeople won't have it as "easy" to be accepted as homosexuals. It's said that people who don't like themself have it harder to be liked by others, let alone be loved. A transwoman has not accepted themself as a man, but then wants society at large to accept them as a woman. It's a very difficult situation and it's not going to get any easier by telling women that transwomen are women. That's just regression, namely that women got their voices heard many years ago, but are now told to shut up again.