So because someone believes that what they're doing is good, they're exempt from criticism?
I think there's absolutely nothing wrong with stating an opinion that you despise someone, despite their intentions. I would say it's fair to dislike someone more based on their personal beliefs, rather than how the act in front of others, in fact I'd say this is logic that everyone will have used in their life at some point.
The person you disagree with who thinks they're right is at least operating from the shared premise that being right matters. Theoretically, that means you can argue and reason with each other. The person who cares only for themselves is outside of rational debate entirely. Being wrong is bad, but being beyond the reach of reason is worse.