The WALL is not only to keep illegal Mexicans out. It would be effective in keeping illegals from all over OUT, along with drugs, etc. It has simply become necessary for social, military, & economic security of the citizens of the USA.
Since Mexico has neither the ability or desire to police that border (unlike their own southern border) it is appropriate that they be taxed or otherwise be forced to cover the cost of the construction & maintenance. If for no other reason, the USA should do that, because we still CAN.
liberals try to link the WALL to racial/cultural prejudice, but like so many of their deliberately misleading, emotional, but brainless howls, that is simply not the case.