I beg to differ, I think my comparison has been misunderstood.
Elbow flexion is elbow flexion, 65% max heart rate is 65% max heart rate, maximum effort is maximum effort. Whether you're sprinting up the court or sprinting towards a line drive if you're going 100% your body is it's ATP-PC & Lactic acid system for that short burst of energy. so on and so forth. Your body doesn't differentiate, it's the function of the movement that determines the risk regardless of what we call the sport. Jumping is jumping, running is running, diving is diving; on a physiological level the body does not discriminate.
Obviously the nature of each sport is different, and puts strains on the human body in different ways; in basketball ankle sprains are much more common for example.
Now just like in basketball how someone could tired from running up and down the court all day I could buy the possibility that shorter periods of rest could tire an arm out quicker. However, I see many pitching injuries as chronic injuries resulting from years and years of unnatural movement, they're not an acute sports injury like rolling an ankle. I think shorter periods of time between pitches just tires pitchers out quicker, and in turn might actually preserve their arms in the long run if it leads to lower pitch counts. I'd be interesting if any studies actually show this in the future that the pitch clock actually curves the rise in injury. However this is purely a hypothesis on my part.
We've clearly seen a dramatic spike in injuries the past couple decades (especially just the last) that correlates and has been corroborated with studies showing it to be a function of throwing harder and an uptick that started well before the pitch clock. I'm open to possibly being wrong, but until there's evidence that's more than just anecdotal that's how I feel.