You're right that I was projecting my personal experiences. The people who I have worked with who called themselves blunt and honest were the same people who never defended an idea and instead resorted to calling everyone else idiots.

Saying you are blunt is often a way to sound superior or right when being rude to someone. Very few problems are as straight forward as 1+1=2, which is easy to state bluntly. Most problems though are more nuanced than that, and I have personally found that people who like to think themselves superior to others like to hide behind words like honest and blunt.