Of course I can explain it. First, it assumes that learning to do dentistry work requires something extraordinary but the only thing it requires is the resources (time and money) to go to school.
Not everyone who gets through school gets high marks, and of those that get high marks not all of them are necessarily inclined to be good with the tools they use.
I've known of some pretty awful dentists who tended to do as much damage to their patients as they did repairs. I have no reason to believe they'd be any better at making burgers or anything else they attempted to do.
And it takes arrogance to believe that a degree makes you superior to those who don't have one. The truth is it takes longer to become proficient in some skilled labor trades than it does to become a dentist, and it take more actual skills to do the work.
I've never met a dentist who could tear down a small block Chevy engine and rebuild it. Not one. I've never even met one that could change the oil on one, but I've known kids who learned how before they were 12 years old.
Finally, some of the most brilliant people in history, some of the greatest engineers, designers, and inventors, are people who spent very little time in school and none at all in any kind of higher education.
If you think everyone who's making your burgers is less intelligent, less capable, less creative, than yourself you are an arrogant fool.