Earlier quoted context omitted.
Years ago I read a book which suggested that this was specific to the U.S.: sitting cross-legged doesn't carry any particular gender / sexuality coding elsewhere.
There are two different kind of cross-legged being described here - the OP means sitting in a chair with your right leg on top of your left, while the reply mentions the floor which suggests the feet-under-thighs position. I can confirm that the former is considered effeminate by some in the UK. The latter perhaps childish.
That’s weird, because no one has ever mentioned anything of the sort to me. Were they particularly small-c conservative?