Mouth breathers, dorks, dweebs get lumped together. Breathe Rite strips commercials tells us not to be a mouth breather.
Why is it looked down on?
I sometimes catch myself mouth breathing and make myself nose breathe. I get slightly congested and compensate without thinking about it. I can’t take Zyrtec too often, My nose, gums and roof of my mouth gets so sore.
Whats the deal with hating on mouth breathers?
Really? The image of someone looking slack-jawed and kinda clueless doesn’t evoke the impression that the person is an idjit to you?
Yep, stereotype idjit. heh.
Sure, if its exaggerated with the mouth wide open. 
A lot of the google images are like that.
You can get a little air with the mouth just barely open.
Ace, you Must Breathe through the nose. I try. Most of the time I do.
Down’s Syndrome often causes improper development of the mouth, teeth, tongue, airway, and lungs; often you’ll see people with Down’s breathing with an open mouth.
I thought that’s where the insult came from.
You know that there are plenty of other options if you need an anti-histamine besides zyrtec. There are also ways to clean your nasal passages without anti-histamines. Go get some generic loratadine or a neti pot.
And the insult doesn’t refer to those who can’t breathe for a stuffed up nose, it is meant to imply that someone is too dumb to work out how to breathe through their nose (which is better for you as then the nasal hairs and sinuses can do their fliltering work). It is also quieter for the rest of the world. It is pretty much the same as slack-jawed - too lazy or dumb to keep mouth closed as decent/intelligent people do.
Seems to me, when I have been congested and resorted to breathing through my mouth, it makes me dehydrated in short order – a bad thing if you have a cold. Perhaps the dehydration attendant to mouth-breathing compromises one’s mental acuity to some extent.
Person who inhales and or exhales with their mouth open /= mouthbreather.
Eli Manning, classic mouth breather…
But one has to do that at times, during strenuous exertion. That’s why we have that facility. The only time I was banned from MB was during choir lessons, outside of practice.
