Think of the personality profile as the impression you're giving to your partner. Impressions are hard to go back and change later. Every time you increase your faith, that's how your partner sees you. It would be hard to believe someone who says "that old me is terrible now, I am changing."
"Action speak louder than words". You can't just say you'd take them all back, you have to show you mean it. If you regret your earlier alignment choices - MAKE DIFFERENT ONES IN THE FUTURE. With a person, the slate cannot be wiped clean, and all your actions forgotten. Why should the game artificially try to make its characters seem more artificial by letting you wipe away the impression you've given?
