So the lats are not actively involved in the throw? The glutes and hip adductors are not actively involved to drive the lower body towards the target? Have you thrown a ball 100 mph? I have, and I know what that feels like. There may not be an active contraction of the triceps or biceps (though the biceps do aid in deceleration), but it’s hard to argue that there isn’t a very strong and active contraction of the internal rotators, lats and torso musculature, in addition to strong contractions from both drive and plant legs.
An athlete does need a certain level of muscular strength to have repeatable explosive mechanics. I think the threshold is different depending on the athlete and the muscle group in question. For example, does an athlete need to be able to squat 500 lbs? Probably not - this level of strength is clearly past the threshold of being useful. Does an athlete need to be able to bench press 300 lbs? Also probably not, especially given the fact that there is less of an active role of that musculature in the throw. Still, in that case if we had a 6’5" pitcher who could barely put up 40 lb dumbbells, that would be worth addressing - we’re talking about a glaring weakness/physical imbalance that would be easily trained, wouldn’t take away from any part of his game - why would you not address that? What about the lats? My opinion from personal experience and the literature on activation patterns says that they play a crucial role in humeral acceleration…so part of this is obviously having the mechanics and motor patterns in place to actually be able to fully recruit those muscle fibers - high level pitchers recruit their lats something like 300% more than low level pitchers. But beyond that, i fail to see an issue with strengthening the musculature that is so clearly heavily involved in throwing.
Sure throwing by nature will strengthen it some - many pitchers have bigger dominant side lats, but let’s say we’re talking about that same 6’5" kid who can do maybe 1 or 2 pull-ups. Are we really going to say that spending 2 hours a week in the weight room and getting him to 12 pull-ups over a 3 month period is going to be counterproductive? It might not help, in every case, but it also won’t hurt in any case to fully strengthen the musculature involved in the act of throwing.
For every tim lincecum or pedro martinez, who have optimized their mechanical efficiency - getting near maximum velocity out of their available musculature, there are hundreds of fringe college players or fringe pro players who are 20, 30, 40 lbs underweight of the “average” major league pitcher (~6’3" 215lbs), and in desperate need of a few mph. Are we seriously going to say to just work on balance and body control and ignore everything else?
Why not construct a multifaceted approach that addresses all these things.
College players spend 40 hours a week with their team
As a pro I spend 60-65 hours a week with my team.
Saying that wasted time is a reason not to resistance train is largely insignificant - 45 minutes, 3 times a week is nothing. Trust me, there is still plenty of time to work on balance and body control (i.e. focused throwing every day).
Again, for every tim lincecum, who probably resistance trained in some fashion despite what you say (remember, bodyweight exercises are still resistance training), there are 10 other successful major league pitchers who have succeeded by including it in their regimen. It doesn’t take away from anything, so I’m not sure why you are against it when it has the potential to help a significant chunk of players (some more than others).