Possibly the most pathetic display of racism ever.

[econ21]

It's human nature when confronted by two evils to pick the lesser one.

I think HoreTore's point is that you don't have to pick - you can, like most public figures would, condemn both kinds of law-breakers. That otherwise decent people identify with one set of villains is, I would agree with the OP, pathetic even if it is "human nature". Pathos and the human condition are scarcely strangers.

I suspect it relates to:

The more local ties the mob has, the better off you are.

Race aside, there can be a surprising amount of support for local mobsters - I am thinking, for example, of some East End villains in London who were held up as local heroes in some pubs etc. I've never really understood it, as the celebrity criminals are invariably rather stupid and dangerous predators. I guess they prey only on a relatively few unfortunates, so the rest can indulge in fantasies about them as heroes without too much risk of being proved wrong.

I was wondering whether people rather side with criminals of the same colour because, if anyone is going to be racist, it is likely to be criminals and hence you are safer with your "own". That might be true if you accidentally stray into the wrong neighbourhood - even a racially blind mugger tends to target the confused newcomer. But because people tend to stay among their own, I am pretty sure criminals tend to prey more on their own communities (black on black crime in the US etc).