This is one reason why people stay as “Guests” and don’t get a log-in name, your posts can be altered from months ago and misquoted against you and there is nothing you can do about it.
This doesn’t happen often, only if you are in a heated debate and you prove the other person wrong. They typically will not tip their hat and concede but rather will resort to personal attacks or in extreme cases alter or delete one of your posts and then use it against you.
Just be conscience that if you do chose a log-in name and are not in line with the “group think” you run the risk of this.