It's reviewers who compared him to Robin Hood. And in the first book, where he has more of a community, there are moments he resembles that. But not here.
As for not being noble, the big appeal of a lovable rogue depends on never examining the morality of his deeds too closely, or assuming that because his victims are rich, they deserve everything he does to them. That also brings in the Robin Hood vibe. But then, if they deserve to be attacked because they're rich, why doesn't Locke deserve to be attacked for being rich?