Most Puzzling Insult

There are plenty of ways to insult people, so why do folks sometimes refer to the preferred oxygen pathway?

As a perpetually nose-clogged person, I take umbrage at the aspersion you cast at those who breathe through their mouths. Use the more politically correct term "dipshit"

— Steve Saideman (@smsaideman) April 24, 2018

Why would a mouthbreather be someone who is not as bright, who is an ape or caveman or whatever?  I just don't get the association.  And, of course, I take it personally since a lifetime of allergies (modest--I can breathe, just not well--to anything that grows: grass, trees, weeds, plants, etc) means I breathe through my mouth.  The only person who should object, and object she does from time to time, is my wife since I don't sleep quietly. 

The key is that the oxygen gets there, one way, or another, so me and my fellow mouthbreathers do not want associations with those who deserve heaps of insults.  Indeed, I discussed with Mrs. Spew the proper way to insult MRAssholes as calling them pussies, for example, is reinforcing their notion that women are lesser (Slack friends also pushed in that direction).  So, calling the guy who killed ten Torontians yesterday a quitter works since he and his ilk (if the info on him is correct) are chock full of failure and toxic masculinity and thus sensitive to being called LOSERS and QUITTERS in ways that don't insult others.

Calling them mouthbreathers?  They probably don't mind, and it confuses me.  So, pick the right insults for these guys who have the attitudes of seven year old boys who don't understand girls.  Most boys grow out of it--these guys don't.