It's not a matter of Lyons having an opinion, it's a matter of him misrepresenting the opinions of Yeh.

You could sloppily quote a book to make the message seem like anything, and it feels like that could border on defamation. A malicious version of this would be lying about somebody to injure their reputation, which is not obviously something you have a right to do.

This case isn't grave or clear-cut so it's not going to go to court or anything like that, but it's still a bit of a jerk move by Lyons.