> This means, if you start a conversation with me in plaintext, I'm obliged to continue exactly as I would if we were talking through encryption. This compels speech,...

I think the author would say that if you don't want to continue in plaintext, you can just not respond.

I don't think so. If you run a server that won't respond to unencrypted requests, I think that would be considered a form of forcing people to use encryption. That's the only way I can interpret "they'll need to make it a crime to force or trick anyone into using stronger encryption than they consent to, no matter how that might be done."

Refusing to respond to unencrypted requests is honestly the only thing I can think of that would really constitute "forcing someone to use encryption." (Unless they mean forcing via threats, but why would they mean that? Who's going around forcing people at gunpoint to encrypt messages?)