Based on what you shared in this post, your sister doesn't know more about the lgbtq. She's only pretending to understand certain things which isn't good because she might mislead/misinform others about lgbtq things.
Had an argument with my sister over who knows more about the LGBTQ community (im a closeted bisexual) for reference, she didn’t know what an orientation was and thought the main LGBTQ flag was the straight ally flag