Power users commonly use fake stories for karma farming. They are sniffed out through the viewing of their post history. Where as my example condenses this idea into a single over the top segment for humorous purposes. A more realistic version of this, would have me being a Vietnam vet one week, and an 23 year old female nurse the next.

Hiding post histories would also hide people posing as conservative in one thread, while posing as liberals in another. People do this to win arguments by feigning association or experience, or out right lying about their actual beliefs.

They do this because they would rather win, then admit that they are wrong, or that their ideals need to be shifted to accommodate a more complex reality being present to them.