They know they are better off than they would be if they were in Africa, which is why none of them would take a free ticket back there if offered.
Tickets (no takers) have been offered several times during the last century to the complainers. They know that the bottom 1% in the US is the top 1% in Africa. They know that a food stamp here is worth more than monkey meat with a side of roots in the Congo.
BTW, the same offer was made to the libs that threatened to emigrate if Reagan, Bush#1 or Bush#2 were elected/re-elected. Again, no takers.