Because local law enforcement says Homeland security won't help,(in the articles) they are only interested in "terrorists". Call a few of them, they'll tell you.
Well then, what are the people who are so worried about this going to do about it? How about writing some letters to the editor, calling your local police department, writing letters to Congress, etc. Let's not just complain about stuff...get active.
And just as an aside, I would take a few people who are quoted anonymously seriously. I'd be completely shocked if Homeland Security wasn't aware of this problem and finding ways to address it.
Where is the line between a criminal gang that crosses international borders, then proceeds to rape, mutilate, kill and rob citizens, and terrorists? ANY widespread criminal activity that serves to intimidate and threaten law-abiding citizens is by its very definition terrorist.
A gang made up of members who have fled their own country, and has reconstituted its objective in another country, is every bit as much a terrorist organization as young men that left Saudi Arabia for Iraq and Afghanistan, and subsequently went into a third country with great mischief in mind.
Homeland Security should be making this sort of activity a much higher priority than has been done up to now. Local police can do the necessary groundwork in locating and capturing these outlaws, but then once captured, the necessary support to ensure these gangsters are NEVER again a threat to the locality should be provided.