Ugh. I f*ckin' loathe the wretched, subhuman pieces of sh*t who engage in that sort of disgusting behavior.
Apart from being really disgusting it makes no goddamn sense at all - There's no logic behind the decision whatsoever.
"Hey, I've got a bunch of snot clogging up my nose, but instead of blowing my nose like a normal human being I'm just going to snort it like cocaine."
A lot of times they swallow afterwards which is so gross it makes me want to hold them down and sh*t in their mouths. They'd probably swallow that, too.