The main arguments against long toss seem to be
it places a lot of stress on your elbow
it changes mechanics and release point
to address the first point, of course ANY kind of max effort throwing is going to place a lot of stress on the elbow. This is an inherent part of overhead throwing…but by being smart and systematic about it, this stress won’t be anything the arm can’t handle.
second off, long toss may use slightly more tilted shoulders to put arc on the ball, but this does not change the fundamental movement patterns when it comes to how the upper/lower half sync up, how the scaps move, etc. Furthermore, proper long toss incorporates a pulldown phase where the max distance throws are translated into shorter and shorter distances as the shoulders level back out again. In other words, proper long toss bridges the mechanical “gap” between throwing on an arc and throwing to a catcher during this pulldown phase.
Anecdotally, long toss of the alan jaeger sort that hundreds of elite velocity throwers do, helps me groove a nice loose arm action and gets my entire delivery feeling extremely explosive and synced up in a way that I would not be if I just started throwing from 60 feet.
long toss may not be for everybody (mostly people who haven’t figured out their footwork, or submarine/some sidearm guys), but it certainly isn’t any more dangerous than any other kind of max throwing. In fact, I would go so far as to say my arm feels way better after a gradual long toss buildup than just going in to throw a bullpen and not letting my arm gradually extend itself. In talking to a fellow NECBL pitcher on our rival summer team at the all star game, he has built himself up to max long tossing every day. Watching him do a trevor bauer crow hop and fire 99mph into the catcher with almost identical mechanics to his 95 mph delivery makes it pretty hard to believe there isn’t some slight correlation. Show me a guy who believes in only throwing to 120 feet, and I’ll show you a guy who is 1) trying to sell something(ex. dick mills), 2) hasn’t been taught how to properly long toss (why I didn’t like it for a long time) or 3) is not or is no longer a player and is more caught up in the theory of what should work (law of specificity) than what actually does work for many many elite throwers.