I should look into that later...
Back round the late 80s, gov't paid rent for immigrants from certain countries (Cuba, Russia, S Korea, etc) got cut from 24 months to 18, and there was an outcry from their advocacy groups. Boo hoo, only 18 free? They still got their grants and interest free loans to start business & go to school, and they have the audacity to complain.
They want to give driver's licenses to illegals in NYC, and I can't get one because I lack sufficient ID! And I was born here! After 9/11, the DMV here made it a requirement to show at least 1 photo ID to get a license, yet us Americans have always been required to show 2 here! They started with a Municipal ID for all (including immigrants) who don't have enough to get State ID, but I haven't been in the mood to stand on line for an hour and a half for some semi illiterate GED dingbat with a God complex to give me a hard time and send me home to fetch some bogus thing (it's a running joke that you have to make 2 trips to the DMV here for everything). But yeah, boo hoo for non citizens, legal or otherwise.
Thing with border walls is the expense and inefficiency. Make a section, they find another route. In addition the enormous expense of a border wide one, there is terrain through which it can't be built. Plus they'll just dig under, or, if desperate enough, catapult themselves over or something crazy like that and splattered illegals would make for bad publicity.