Think about it, Damon and Kat are the same:
-They both spent a lifetime of doing selfish horrible things -They both came back to Mystic Falls with a selfish purpose -They both decided to change because of a person they love
Sure, Kat may have pissed off more people, but she also lost her child, had her entire family murdered by Klaus and then had to run from him and be alone for 500 years. She had many more excuses to lose it. None of what Damon went through can compare.