I mean first and foremost, the objective of the camp has to be for the kids to have fun, enjoy baseball and make some friends. That said, baseball is a difficult sport for kids and learning the fundamentals (in a fun way) for younger kids (5 through 7) isn't insane. I've been coaching kids from about age 4 to age 10 now over the past 5 years and it's alarming how quickly they develop bad fundamentals and mechanics that become very difficult to correct. When coaching 8 and 9 year old kids, you spend most of practice trying to correct bad habits they developed when they were 5 through 7. And guess what - kids with bad fundamentals typically don't have success, which leads to less enjoyment and them ultimately quitting.
Do you need ex. professionals to do this? Obviously not, but I think that just adds to the fun part for kids. It can be special to know you're at a camp with guys who played or coached at the MLB level. If you want to argue it's nuts to spend that much on your 5 year old - be my guest, but if you have the extra cash and think your kid will have fun, I won't judge.