Do you read what other people post on this site?
I'll start with the 2 you disallowed.
1) You can have a welfare state, unlimited franchise, OR open borders. Pick two. Otherwise you'll no longer have money/non-socialist/ non-dictatorship country. Import people who vote for socialists in their country and SHOCKINGLY, they vote for socialists who promise free stuff here.
2) Importing unskilled labor impacts those at the lowest end of the economic stratum far more, including those recently immigrated. This not only harms our citizens, who should be what our government is concerned about, this also makes the "voting for socialism" more likely, too.
These are not unimportant issues, but most libertarians like to pretend that they can just stand on "MUH PRINCIPLES!!!" based on some theoretically perfect world with no regard to the impact in this real world. (Kind of like socialists, in that regard.)
Now, for the ones you think are "justifiable" arguments, they are myriad as well.
1) Crime: Importing unskilled, unvetted, often illiterate aliens increases the crime rate*
2) "Multi-Culturalism"/Social Cohesion: Our country is currently either at or above, the historical maximum of foreign born population. Any country requires a significant amount of cohesion, and having such a large percentage of assimilated residents will necessarily cause conflict.
3) Disease: We already have enough idiots attacking herd immunity through anti-vaxx opinions, we don't need to import more unvaccinated, possibly diseased individuals with zero vetting. (Honestly, this is the least of my concerns, but if you want to include it, fine by me.)
4) Terrorism: I'm sure you'll have no problem with the resulting government over-reach in order to track which of the completely unvetted and unknown immigrants are terrorists. Much easier to use the NSA, FBI, and the lot to track EVERYONE'S activities, rather than limit who comes into the country and thoroughly vet them.
There's a BRIEF run down on some of the arguments.
*Oh, but THE CATO STUDY! that completely agrees with what I just said. The study liked to tout how immigrants were more law abiding!!! (small print- than citizens of similar demographics in the country). So what it means, aside from conflating legal and illegal immigrants, as such studies are wont to do, they found that the immigrants had a higher crime rate than the average of the country, but since they were better than the native hispanic/white/black/asian/other population's crime rate, well, THEY ARE MORE LAW ABIDING! Of course, the study also makes me wonder what the rates of the citizen children of those immigrants will be. Just guessing it will be closer to the native hispanic/black/white/asian/other population.
Everything I have seen/heard says there is higher percentage of
illegal immigrants who are criminals than the rest of the population.
Also, When it is said that we reject someone today, do they actually go home? How many of these crimes do we see the suspect was deported a handful of times?
As far as I know, if someone shows up at the border, they just claim asylum, they get a preliminary hearing, then they are let go into the US until their hearing later. Our laws are set up with loopholes you could drive a truck through. IMO, there is no comparison to what we were doing 150 years ago.
Also, people forget that after the waves of immigration in the late 1800's and early 1900's, we nearly shut down immigration for quite a few years. I think it wasn't until after WWII that we relaxed some of that.
