Yeah it seems like the parent is thinking that being rude and blunt is the only way to maintain integrity. It’s actually surprisingly easy to maintain integrity and be a likeable person.

Just think of the the protagonist in "Shawshank Redemption". I don't mean "look, how easy", but I would be surprised if most people don't respect that character in some form. He doesn't hate others, he's not arrogant, he just also doesn't give in, and I would say he holds on to integrity for his own as well as everybodies' sake, not as something he wants just for himself to then judge others with. Even if it ended differently, I think most people would still say "good for him" for how he carries himself. Ultimately, I think communities, at least smaller ones in real life that aren't dysfunctional, are really good at knowing where one's heart is at, and that matters more than anything.

The way it was written, I'm reading between the lines that your parent comment is describing their own personal life experience, where they are the "person with integrity", and generalizing it to the world.

Going just a bit further, I would observe that people I have felt best modeled integrity... do not openly identify themselves as "someone of integrity". It's just something they do, it's just the way they are.