Who makes up etiquette rules ?

Apparently I've been eating bread wrong my entire life.  I read something in a book recently that suggested that I have been departing from societal norms, so I looked it up.  Here's Rule #3:

"The only correct way to butter and eat your bread is to:

Using a knife, put a bit of butter on the side of your bread plate first;

Then, tear off one bite-sized piece of bread at a time and butter that piece only, right before putting it into your mouth.

Many people make the mistake of buttering the whole slice of bread and then biting into the slice."

I quite understand not to do any "communal dipping" into olive oil (Rule #7) (and not to double-dip nachos into the group salsa), but who determines that bread is placed on the left (Rule #2) and passed to the right (Rule #6), or that at formal/business dinners, bread should not be eaten until the first course is served (Rule #1).  

Hygiene and health-related rules are fine, but other prescriptivist dogma seems archaic and silly.  IMO.