[I was going to illustrate this with a picture of the little Syrian boy who drowned at sea but looking at it was so painful that I couldn't.]
She really is loathsome.
Shorter Megan McArdle: Increasing immigration by .5% will lead to a "societal meltdown."
Shorter Unstated Megan McArdle: Since it is unthinkable for a non-Muslim woman to marry a Muslim man, we might let more Muslim women immigrate but increasing Muslim immigration .5% by letting in Muslim women to marry Muslim male immigrants will lead to a "societal meltdown" because Muslims will strain "both the political and social systems" they enter in anything but negligible numbers.
See also for context.
We can't help the desperate because it would destroy our way of life. We can't let the banks fail because it would destroy our way of life. We can't have single payer health care because it would destroy our way of life. We can't lower the financial industry's profits because it would destroy our way of life.
I'm beginning to think that perhaps Megan McArdle doesn't want to help anybody but Megan McArdle, and therefore her constituency of one makes her both a narcissist (Thanks, anon.!) and a danger to everyone else.