> I have never heard of anyone getting injured from dumbbell curls or lateral raises, but everyone I know has tweaked something from a momentary lapse of form in compound movements. Turns out moving 400lb+ pounds close to your limit regularly isn't that safe.
That's because by "getting injured" you're thinking of "a momentary lapse of form." As an old guy, I can tell you the injuries to look out for happen slowly, then suddenly, when muscle imbalances accumulate and inflammation starts to happen more than the body can recover from it, repeatedly and over a period of time. Tweaking a muscle is nothing, muscle imbalances and joint pain are the fun stuff. Since bicep curls are not functional movements, they're prone to these muscle imbalances. A pullup or chinup (even weighted) is a counter-example, and a more natural human movement. Having huge, very strong biceps and not ensuring the triceps keep up (and not to mention the muscles in the forearm) is more likely to result in pain at some point. Probably pain in the elbows. You also hear of muscle / tendon tears (you can see some of them on YouTube if you can stomach it) while the exercise is performed.
> Turns out moving 400lb+ pounds close to your limit regularly isn't that safe.
Maybe some of your arguments are just wrong ? 400 lbs isn't a meaningful number in isolation. And moving what, as in squatting? It depends on your weight class and training levels but 400 lbs of squatting isn't a recipe for damage and death if you've built up to it with good form. Why would it be? Which part of the anatomy do you think will suffer first?