Are Patrick and John Collison terrible people? My impression is quite the opposite; they're smart, hard working, and care deeply about making the world a better place.
There's a Canadian billionaire who is famously always donating to hospitals and suchlike. He's had tens of thousands of employees for decades and I've never heard anyone say anything bad about him.
I know another billionaire in Vancouver who isn't known for donations. Actually most people don't know he's a billionaire. He is generous though; he just insists on being anonymous when he gives large amounts.
I suspect the issue is less "billionaires are horrible people" and more "the highest profile individuals from any group tend to be the narcissists".