BBC seems to have left sex at the door and gone flying off with gender-feels with this one.
Which makes for much confusion about sexual feelings (particularly if you're young, trying to work out who you are, and happen to be reading that article)
Many people feel uncomfortable with the idea that there are other sexualities besides being straight and that people can identify with a gender that is different to their sex.
Those two statements don't work together - different sexualities. (ie being attracted to sexes other than the 'traditional' straight M + F. But also suddenly,... your gender doesn't = sex. So what on earth does 'sexuality' become? )
"Out-dated LGB" = about attraction to sex. You know, the body stuff, outdated fuddy duddy stuff!
T = decouples sex from 'gender' stereotypes and presentation, regardless of your reality-based sex. You're attracted to stereotypes associated with a certain sex, regardless of the body it's attached to.
The question becomes who's uncomfortable about what? Sex? Gender? What is 'straight' when gender doesn't = sex?
The TQIA+ end of the spectrum seems to be really having to reach to justify their point of view right now.
And organisations like the BBC seem to be up for helping them reach up to that gender-fairy-sky to argue their case, even when it makes absolutely no fucking sense at all!