The people in the caravan are just doing what Republicans have claimed they wanted prospective migrants to do all along - stop trying to sneak across the border and find a legal way in. Walking in large groups is the only way they can do this safely, if you are really concerned about this then we could just fly them all here for a fraction of the cost of deploying troops at the border to pose for the cameras.
The fundamental reality is that Americans are entirely dependent on cheap immigrant labor, and because the second generation quickly assimilates into the mainstream and has no more desire to do dirty low-paying jobs than any other American, this means we have to constantly bring in new workers from further and further afield to fill those roles. The GOP's "solution" to this is basically to try and create a permanent servant class who will never be able to attain equal status, and are so paralyzed by fear of arrest and deportation that they will never agitate for their rights. Ironically, this kind of policy would accelerate the demographic shifts that conservatives are always fearmongering about because employers could bring in cheap foreign workers en masse without any fear that their children will one day become competitors for wealth and influence. Just look at some of the Arab countries, where the citizens are outnumbered many times over by migrant workers who endure appalling working conditions and have no outlet to press for better treatment.