Ah yes. I was confused by your response. That makes more sense. No, I generally don't ask push others to use text-based email, but when asked, I explain the difference with a definite preference for text.

One thing that seems to have helped me (but is very much YMMV), is when I reply, it keeps the html code all messed up. Then when the person I'm discussing with sees that, they'll occasionally ask me why their email is messed up. That gives me an opportunity to explain html vs text, and they usually would rather their email "work everywhere".