Yet another weirdly-judgmental thread from the same person. I wonder if the tone of them is recursively related to why the tone is there...

Anyway, two of the jobs you've listed are actually very important. Not everyone is going to take perfect care of their teeth, even if they can, and sometimes things happen that people can't control. Enter the Dentist. Now, there's an expert who specifically trained in this area, ready to take care of an important part of a person's health. Likewise, people in hazard suits wear them for a reason, and I'm sure there are plenty of jobs involving them which aren't exclusively tied to wearing one. Unless you'd prefer people clean up dangerous chemicals, radioactive waste, and various biohazards, all without protective equipment?

To summarise: Dentists exist because some people actually care about and understand the importance of oral hygiene and want to help others with it. Hazard suits exist because hazards need to be cleaned up, and nobody wants to do that without proper protection. As for horror actors, I mean... If you don't like those movies, nobody's making you watch them.