One visit to the REE thread demonstrates pretty clearly why it is locked.
Yes, much like marketplace scammers you can't have anyone disputing your claims about what you're selling (a plea to remove a moderator). Nice to have the exposure of Meta without having to deal with open discussion.
That is the problem with removing the ability to use locked threads, people can just drown you out with sheer volume of posts. People being able to speak freely is a problem for some people like Suchmoon.
It's a bit of stretch to frame you talking to yourself as "free speech" but even then - I don't have a problem with it. Knock yourself out. I just don't think your self-inflicted problem should be a hurdle for implementing OP's suggestion.