Some people just don't give a damn. They say what they think, without thinking how they might sound. They are direct, honest.
Too many of us pay way too much attention on how they appear. We make sure we don't say anything wrong. We don't want to appear rude or hurt others feelings.
There is nothing wrong being polite and considerable, but sometimes we need to hear the truth. No matter how ugly it might be. We need to know where we suck so that we can improve ourself in those areas.
Those who speak directly may appear blunt and rude. It might be harder to get to know them. But when you do they can give you so much.
I'm lucky to know few such people. I really appriciate their feedback. I can be sure they are telling the truth no matter what. And when they say something is good you can be sure they are not just saying so to make you feel better.