from the people I know who work there, yeah, there's a bit more bad ones than at other places for sure.

Though I blame it more on their slightly looser hiring practices. A lot of people get hired there that have no business working as engineers on hard problems anywhere. Then Amazon does what most tech companies seem to have trouble doing: can them (they should not have hired them in the first place, but still). Then they write stories about it complaining about how great they were and were canned.