Because nationwide homicide rates in comparison to the worst-city homicide rates has anything at all to do with the personal asylum stories of immigrants.
Sure, if someone is dumb enough to show up at the border and their argument for coming is overall homicide rates instead of a personal story of violence that is not able to be corrected by the corrupt authorities then, of course, send them back. But, I meet a lot of immigrants and hear a lot of stories. None of them that I have met have actually been stupid enough to think like that.