"Too many" is kind of a hilarious answer. It implies that there's a good or right mix of demographics for mass shooters, and, to Charlie, that mix should include fewer trans people. "Mass shooters should be cisgendered!" is a logical reframe of his position and it's just, like … what are you even saying?

I like this interpretation. The right is saying that being trans is a mental illness removing their right to bear arms. But what if they're simply saying that being trans should remove your right to be a mass shooter? That the right to be a mass shooter should be something that is reserved solely for cisgendered individuals?