Its the terseness -- I think its ok to be terse with people you know, but in a context where you're interacting with someone who doesnt know you well, manners can be pretty important for relaying that you're on the same team. Directness can come across as aggressive when you cant see a persons expression or hear their tone. Especially if its a sensitive subject.
I just got reported to HR because I told somebody that a component they developed for us was badly designed. Turns out everybody agreed and it was changed but I still have to deal with HR.
Being ultra sensitive keeps people around you on their toes and makes them think twice about everything they say.
I think running to a manager and complaining about being offended is the new way of bullying people.
