Drugs brought by Mexican cartels?
People don't understand the addict mentality. Live in a box? Check. Defecate under a street lamp? Check. It's worth it for the ability to stay high. The high of the addict is all that matters. Everything else is secondary.
And when these dregs of society find a bunch of lazy cops, and lazy city administrators, and liberal fools, all of whom enable them to stay stoned, said addicts will flood to that city. LA. San fran. Portland. Seattle. Juno, Alaska. It doesn't matter. They'll find a way.