I know it’s a bit difficult, coming from your bubble and all but most things people do are not related to their sexuality but personality. If you saw a hetero guy or gal post selfies like that you would also not think of them being hetero as the reason why they do this but because they like this pose / think they look cute like that.

This is an unconscious bias. It takes some time to rewire your brain. But I see you are willing to and that’s already the best start.