Why not? Because it assumes world and even plane spanning criminal organizations. I don't assume that in my campaign world.But that's not what it says - so that's an easy one!
And here's the "why not" question. all it allows you to do is get a message to your contact, whether that will be of real benefit - that's not what the feature does. ALL it says is, criminal organizations tend to be similar and a true criminal (the background) has a good understanding of how they work and can exploit that, even somewhere they've never been before.
It's meant to be a roleplaying aid not an I win button.
If they're in a TRULY alien place where NOTHING works as they know it to? well that's a different story and that's the challenge.
Someone who has a criminal background because they were a runner for Nine fingers Malone in some backwater city in no way has those kind of contacts around the world.