Everybody agrees that democracy is not the ultimate value: if a majority favours killing all Jews it doesn't matter, you still don't do it. But how do you know which things are "just wrong"? You can't vote on it.
An argument against immigration (which I think is pretty good) is that the immigrants could come in and vote for horrible illiberal things, possibly undermining women’s rights, to take an example. So we say, "we have the power and we won't give you any because we worry what you will do with it."
That might sound ok, but the same argument could have been used to deny women the vote. Back in the day, men had all the power and there was a pretty good classical liberal status quo. Women like taxes and lots of other stuff that libertarians regard as rights violations. So men could deny women the right to vote for exactly the same reson as keeping foreigners out.
How is this argument against immigration different to the argument that women shouldn't vote?
These days it seems self evident that women should vote, but it hasn't always been this way. Opponents of immigration think it's self evident that immigrants have no right to enter. Proponents instinctively feel that people should be able to move around as they like.
How do you decide questions like this?