How do you have any idea what's socially determined (a more neutral phrasing than "contagious") and what's not? It's not as if anyone's doing randomised controlled trials of RuPauls Drag Race exposure and gender self-identification.

I don't care why people do anything and I'm generally happy to let them do it, but come on. We have no idea what causes any given person's sexuality or identity to develop in the way it does. The most you can do is point to some correlations. Definitive statements like that are overconfident.