First of all, in the aggregate, Ireland was hardly sending its best and brightest to the States (as crime statistics bear out), so in some ways, the comparison is not quite fair. (I am of Irish heritage, for the record.) As for other groups, the assimilation of the Irish was a rough and messy process. There was indeed unjust discrimination from the Anglo-Protestant majority, but there was also a lot of insularity (perhaps reinforced by unjust discrimination) and unwillingness to integrate for a while. But regardless, the Irish still largely spoke English and were part of a common Western cultural tradition that made for easier assimilation in the long run. A significant portion of their descendants converted to Protestantism or intermarried with Protestants and had fully "American" children.
It would be one thing if we were taking in Lebanese Maronites, but parochial Sunnis from Yemen or Somalia are a whole different ballgame. To think that the same process with the Irish and others can be replicated, at least in the next half-century, for the most backward elements of the most culturally backward and poor parts of the earth is laughable.
1 I am all for enlightened members of those groups to immigrate here, and in fact, I would be happy to exchange some of our worst elements for the best of theirs. Unfortunately, the government is both unable and unwilling to micro-target immigrants to that extent, so it becomes necessary to impose collective restrictions.
It would not matter so much if the Somalis and Yemenis coming here were, let's say, Buddhist, but they instead follow a religion that is fundamentally at odds with Enlightenment values and that reinforces their own stone-age cultural mores. Too many people think that Islam can be easily turned into a kind of cafeteria Catholicism and readily adapted to the West. The fact is, this just is not the case.
Individual exceptions (i.e., nonobservant Muslims) do not negate the rule or alter the religion. This, of course, can change, but why should my country have to be a petri dish for this process? It would be very magnanimous of us to do it, but you cannot expect people to put up with it. Immigration should be a policy used to benefit
the country, not the immigrant. Thanks to the reckless actions of the Empress of Europe and those of greedy, near-sighted West German politicians of the 1960s and '70s acting under American pressure, your country may yet have the honor of proving me wrong. I doubt though that either one of us will live to see it.
1. All people are inherently equal (race is a fiction), but not all cultures are equal, and we should not be ashamed to say it or to adjust our immigration laws accordingly.