I'm genuinely in two minds here OP - wasn't that polite? 
I'm quite direct, except I never announce it as such. To me, I'm expressing my opinion and am baffled when people get hurt by it, especially when they've asked for it.
I don't think I'm on the spectrum, but what do I know?
I'm not without tact though. I generally don't express a negative opinion on personal subjects, because I know that's probably not what the person wants, even if they've asked.
Actually a close friend was doing some kind of weird, culty thing where she had to ask people for their genuine opinions on her - the worse, the better. She wanted me to tell her the truth but it was really hard. I managed to say some things, but not: 'How much are you paying these charlatans to tell you you're useless, you fool?'
What I'm talking about is when someone gets huffy because you have a different opinion to them and express it quite forcefully. I find that passive aggressive or just plain old weedy. There are so many people like that about. Usually they announce themselves by saying: 'If you have nothing nice to say, then you shouldn't say anything' or, 'I hate confrontation.'
I find that as irritating as you find people saying: 'I'm just being direct.'
I was reading a thread about book club politics yesterday that reminded me why I don't belong to one. We once had what I thought was a harmless conversation at work about books and I said I didn't like the book someone had said was her favourite and listed my reasons and she behaved as if I'd called her baby an ugly little troll.
OTOH my MIL has a habit of saying things that she suspects I will object to: women, unions, left-wing politics and laughs: 'Ooh! That's just me being controversial.'
No, that's just you being annoying and I'm not going to bite because you are essentially a nice woman.
I also hate people who don't suffer fools gladly. That always says to me: 'this person is an intolerant arsehole and you really should end the conversation right now.'
And yes, I suppose the book club politics bit was a fred about a fred. Or taken another way, just me being illustrative.