If you were to then complain, "But it is illegal to allow strangers to trespass into my home." We might reply, "We will pass a 'bayourod law' and make it officially legal. Then you'll have no complaint and you'll feel better."
: )
I can give you many actual reasons why I would oppose that. But I certainly would not say something stupid like " I'm against it only because it is illegal."
If you like legal immigrants but don't like illegal immigrants for the sole reason that they are illegal, then, by definition, you will like the illegal ones after they become legal.