Purple Sage makes a great point: what is generally called “misgendering” is really “missexing.” It is a failure to identify biological sex. This is why transgender people fail so much at “gendering” correctly.
I hope this illustrates what’s happening when trans activists choose neutral or male pronouns for lesbians—they are implicitly saying that the lesbian is something other than a woman. This is rooted in sexism and homophobia—the belief that women should look a certain way and that homosexual females aren’t real women. The idea that homosexuals are really “men trapped in women’s bodies” or “a male mind in a female body” is an old, homophobic belief that came from early heterosexual sexologists who were trying to explain homosexuality and defining it in terms of heterosexual belief systems. Now the trans cult is promoting the exact same thing and calling it progressive. So many FtM videos I watch are young lesbians who came out as lesbian and then after watching a lot of YouTube videos decided they were really “men,” based on really silly things like wanting to wear “men’s clothing” and have a short hair cut. They are completely normal lesbians who have been convinced they’re not women. This is homophobia and it breaks my heart every time I see it.
Calling a masculine female by male pronouns, even if that’s what she has requested, is rooted in the idea that a masculine female is not a real woman. I think that’s what’s insulting. It’s not insulting to identify a female as a female, because being female is not an insult. But going along with the idea that certain women aren’t doing woman right, based on incorrect cultural ideas about what a woman is, is insulting.