Youth baseball is completely different than pros - kids throw way fewer pitches way less frequently. With the exception of extreme high school/college coaches, but those coaches will be extreme regardless.
I would like to push back on that a little. It is very common (again, anecdotally at least with the 16 K-12 districts I work with regularly) for kids to be on multiple teams. They'll do a summer league, fall/winter/spring weekend league and weeknight league. It is not uncommon for kids to be on 2 teams through the school year, and 3 in the summer. So, while there are rules around how many innings one kid can pitch, and how many pitches they can throw, there is no governing board to oversee that. It's all honor system; parents are in control of that. It tends to be more flexible than the rules actually intend.
The logic goes “we need to get these kids ready for college, so they’re used to it.”
It’s certainly plausible.
If studying medicine it's easy enough in the USA that the tough part is getting admission (which I doubt) then I think your priority would be to fix your degree courses rather than fiddling with the admissions process. It's still weird to me that you can get into university by throwing the ball good, but if someone can balance what is basically a unpaid professional athletics career and get a decent degree too then more power to them.
This is not how any of it works. At all.
A quick search is just showing studies on sports participation and children's health while they are still children (which seems to be resoundingly positive).
Any kind of relevant metric, such as future injury of health, academic success in a non-sports-scolarship program, future propensity to crime etc etc. are strongly influenced if you simply are the kind of person that is likely to enroll into sports.
The article goes into it, but the more likely culprits are starting pitchers throwing harder, throwing more sliders, pitching without foreign substances (so they grip the ball harder), and obsessing over spin rate.
There are three local high schoolers who have had Tommy John surgery. It's like they're proud of it.
An it's terrifying. If the pitch clock comes into these leagues (and it will because why not treat 6 year olds like they're pro-players so the dads can live out some weird fantasy) we will see more and more youth with injuries.