Many lgbt teenagers and young adults growing up on the internet today have socially conservative beliefs that they voice at all times that they got from their conservative parents which they’ve never challenged because they think the life experience of being gay or trans makes them politically progressive
This is why I hate it when people say something homophobic and then go “so you’re really accusing me, a whole ass lesbian, of being homophobic 🙄” like yeah
There's a model of culture that I like to cite for this idea, called the Iceberg Model:
The LGBT youth (and young atheists, too) will cut off the stuff "above the water" but not really examine the stuff down below that line that they have as part of their upbringing.
So you get young LGBT people making comments like OP cited, or young atheists acting with an Evangelical persecution complex, and going, "Don't call me Culturally Christian!"
This is the sort of thing I keep talking about when I’m saying identity is not the same as ideology.
Who you identify as (who you are) says absolutely nothing about what you believe (your ideology).
Same goes for any subcategory.
“I can’t be racist, I’m black.” If you're making “ching-chong” jokes about Asian people, you’re still racist.
“I’m can’t be misogynistic, I’m a trans woman.” If you’re slut-shaming sex workers, you’re misogynistic.
“I can’t be queerphobic, I’m non-binary.” If you’re saying bi/pan/trans people can’t bring their hetero partner to Pride, gueeeess what.
Punching down within your own culture is still punching down.
Also people disagreeing with you doesn’t mean they’re any kind of -phobic if the argument has nothing to do with your identity. You’d think this is obvious but some insecure/unhealed people really do use that attack against others as soon as they encounter any disagreement or conflict. And the tone of discourse these days encourages people to believe those accusations without questioning.