Social Media/Forum posts will definitely be used by a prosecutor if someone is ever in a physical self-defense incident. Good point, @WildRose.
And unfortunately, deleting will not 100% remove the post. The only way to improve your online standing is to show you’ve learned and grown after making comments that are off target. It’s a battle that can be won, but it will be an expensive battle and there are no guarantees it won’t taint a jury against the person who had to defend themselves.