I don’t think anyone’s arguing that it’s impolite to unplug one’s respiratory tract in a restroom when necessary. But what I object to is the method: what’s wrong with a good, healthy nose-blow, or a throat-clearing followed by a spit? Personally, I’ve always been able to get rid of what needs gotten rid of without making noises like a bull moose in rut.
In college, one of my roommates had a cold that lasted all winter long (and that’s a long time in Ohio.) I had to sleep in the same room with him and listen to him loudly hock and swallow every 2 minutes until he fell asleep. By the end of the winter, I was rethinking my position on gun control.