Their contribution to this problem doesn't necessarily have to be a negative thing. Saying they made a contribution isn't an accusation. No one is saying that they should stop doing business in California or that they should try and succeed less, whatever that might mean. However, they do contribute to the runaway social inequality in the state. Every high paying employer does, including mine.

This doesn't mean they necessarily have an obligation to do anything about it and again, it also doesn't mean it's a bad thing. It's an inevitable side effect of their success. They did business, made a ton of money, spread it around, and one of the myriad indirect consequences is social inequality which contributes to the housing problem. Again, it's not a bad thing per se, but it's a real thing. The fact that it wasn't a bad thing doesn't mean there is no moral responsibility attached.

It's nice to see a company trying to deal with the consequences of their actions without being forced to.