Sam is not an asshole. His twitter is great, he's definitely opinionated, and if you haven't had the luck of meeting him you might misread his tone as grumpy. It's not. It's sarcastic/dry humour and honest.
They build good stuff and care.
His X.com persona is def that of an asshole.
You can build good stuff, care, and be very opinionated...you can also be all of those things and still be an asshole.