What about post histories, even if you change your visible username to something else in order to make a post, the post is still going to show up in your post history, so once people are able to guess that it is used based on writing style, signature, personal text, etc, they would check your post history to confirm that it is you who made the post. I think it is better to stick with this:
I don't have a problem with alt accounts as long as they're not used for evading bans. If you're hesitant to say something controversial because you don't want it to be associated with your name, please create an alt account and say it.