It's a thing insofar as gay people allow it to be one. I've never experienced pressure from another gay guy to do drag / cross-dressing -- but there is that stereotype we encounter, where certain straight people will assume you're willing to do drag (or love the color pink) as soon as they find out you're gay.

As far as your second question: Yes, you're absolutely right that there has always been heteronormativity present within the LGBT+ community. I think the sticking point is: At what juncture do we let it spiral out of control? If any of our values or customs would be perceived as heteronormativity...is it due to our own sovereignty, or is it based on an unreasonable pressure to "fit in" with straight society?