That incident catalyzed the fear that suppressed my desire to participate online for months. I figured that if I couldn't talk about it now, I might never participate again.

Good on you.

Honestly, if there's any chance the content they posted on your profile before locking you out comes close to defamation, I'd consider talking to a lawyer about it. It could be that getting one to send them a cease-and-desist letter on your behalf could take care of the problem.