Why is farting socially unacceptable?

Using your example:

A sneeze comes from the mouth. Gas is passed through the anus, which is a part of the body that many people find taboo due to it's function of eliminating waste.

Although the mouth can be a disturbing orifice due to the words that can be spoken from it, the mouth is mostly considered a "friendly" part of the body. The mouth kisses and smiles, while being associated with wonderful things. Eating, laughing and singing are all positive things that come out of the mouth.

We all know what comes out of the anus. So, no wonder smelly farts are not socially acceptable.

While it is unofficially acknowledged that we all have gas, officially it is considered inappropriate to share this bodily function with the social world due to the odor and embarrassment it can possibly cause. We all do it but no one talks about it, and because this function is omitted from what is considered a private area, as opposed to a sneeze which says hello from the more acceptable nasal passage, it is socially preferable to not share with those around us.

It stinks for sure + unpleasant to hear especially when it makes a 'tone/melody' while farting (which does happened for some) and overall just disgusting.

Maybe because a fart smells and when you sneeze it's said your heart stops for a moment.

Because it's a disgusting human body process, that is stinky and unappealing. Sneezing is ALSO gross, but it is contained in a person's hands when they do it, not spreading through the air where people can smell it.

Uh, sneezing doesn't smell like lightning hit an outhouse.

It smells.

Have a polite day.

Etiquette takes over where laws end.

Because you can prevent it and it smells terrible.

for one thing,,,,it smells