Absolutely, its a no win, but mass migration is a no win either, so you could argue, why bother letting them in, leave them to it too.
I dont mean that as a inflammatory comment to your valid points, but there has to be a better solution than either scenario. Its like a disease, pointless just treating the effects, you have to tackle the cause to make it stop.
I guess its easy to say, what was the point in getting involved in Iraq and Afghanistan, are things better off for our intervention, well, we really cant say what would have happened if we had left Saddam to it and same goes for the Taliban. A topic for another time i guess.