The Internet is filled with people who think their opinion carries more weight than it actually does, especially the people who've watched too many episodes of "Chopped" or "Top Chef" and think they know everything about the art of cuisine.
This phenomenon is essentially responsible for the success of websites like Yelp, which can be a useful resource if you can find a way to ignore the people who take joy in leaving scathing reviews and barely decipherable rants (as well as some of the questionable business tactics).
While restaurants can technically respond to the criticism online, more often than not they're fighting a losing battle. Unfortunately, there's no way for them to rate the people they serve, although I'm sure anyone who invented such a thing would be a savior to the customer service industry.
This is especially true for the people who deliver your food -- the ones who have to deal with issues your typical server will never have to encounter.