Mexico doesn't want them, most come from south of Mexico where it's even worse. It's in Mexico's best interests to let them pass through and aid them as much as they can in getting into the US.

I'm Libertarian and have a mostly positive view of POTUS decisions, don't agree with all but enough to vote for him if Jo wasn't campaigning. I can vote for her because my state is solid red and an additional Trump vote here is meaningless.