Yes, because if we hear it, we'll begin to believe it and it'll make us all sexist as a result.
Well, you may have a point. Theists still try to argue the case that creationism is a legitimate theory and scientist won't even talk about it or debate it because it clearly isn't science and shouldn't be treated as such... and people still believe them.
Hopefully someone was around to slap em with a mute or a boot out of the lobby. The 'harm' happens when you let little shitheads like that goad you and get you frustrated. Which is what they want... so in that respect, you're letting 'em win.
In the great email box of life, you get a lot of spam. So when you see something stupid like that, it goes in the spam folder and the sender is put on the blocked list. If you think someone like that is actually persuading anyone to believe something like what he's suggesting, then there's a problem with you.