Research has shown that immigrants (including undocumented) have a positive effect upon reducing crime rates. Even where there are pandemic issues like violence and drugs, the factor most relevant was employment.
That's clear bunkum. One only has to look at the disproportionate number of illegal immigrants who are convicted of serious crimes.
Like most of these BS propagandist studies, it "conveniently" mixes up legal immigrants who are overwhelmingly law abiding, intelligent and hard working and who do bring benefits to the host country to water down the crimes that illegal immigrants commit.
It's deliberately deceptive to change the meaning of the data for political purposes. No different than if you included men when tabulating the rate of "death by childbirth" so it gave a lower number - it's a different group entirely.
Show the stats for each group separately and then we'll have a meaningful discussion about illegal immigrants.
I don't think anyone objects to legal immigration as long as there is a fair and sensible process. Anyone saying that Mexicans should not be allowed to enter the US legally would be racist, but that's not what anyone is saying, it's not what Trump is saying and it's not what conservatives are saying.