I think at some places it starts off as the "no asshole rule", but then as you start hiring more people like the rest of the team, that will lead to actual disc

I think at some places it starts off as the "no asshole rule", but then as you start hiring more people like the rest of the team, that will lead to actual discrimination. If you have a team of early 30 somethings, they may not want a young 20 something or an older 40 something on the team because, well, they're not like the other team members. And it's not always explicitly "we don't want 40 somethings". It is simply implicit in the way you hire. But implicit or explicit, it's still wrong.