edit: given the ambiguous nature of the headline, maybe you were referring to immigrants as a whole and not simply people who migrated here illegally. In that case I agree with you, but given the context of the article I think they meant to refer to illegal immigrants. This, of course, doesn't make much sense because there are penalties for hiring illegal immigrants. The article hardly mentions immigrants, and it isn't clear which category they refer to. I don't think there is a broad assumption that immigrants on the whole are unemployable, as the article claims.
I'd like to see some clarification from Grist.
I think you have your ranking backwards. Having committed a crime means you screwed up. Being an addict means a life-destroying drive that never truly goes away.
It doesn't mean never hire them, but it does mean don't put them in a position where they have a larger ability to hurt others.
Obviously some crimes are of the "stupid teen" variety, and other motivations - those should be categorized differently.