I’m not an authority on copyright, nor did I claim to be. I’m just aware of my surroundings.
And again, even if courts suddenly decide that training AI isn’t fair use, you don’t have to attach a license to your comments for it to apply. Content that you produce is copyrighted by default, with all rights reserved. You are exclusively giving away rights by attaching a CC license, not reserving them.
You should reconsider that, because you are most definitely giving up many of your rights to your content.