You also have much more room as a bike. If I'm passing someone going uphill, and I don't have enough power to finish the pass on the hill, I have another 8 feet of lateral buffer versus a car before they would come dangerously close to me.

I'm not saying you should hang out next to cars all the time, but it's better than in a car, where you might have 3 feet of buffer.

A bike, generally, can't brake faster than a car, no?

Depends on the bike, but usually a little less stopping power at lower speeds. Above 45mph or so, it's a wash. Bigger bikes also stop slower.

It is the seemingly prevailing train of thought even if it isn't exactly accurate. But why should that stop it from being believed?

ABS on bikes has largely erased the difference.