Some good perspective on why crossfit has a bad reputation for injury and probably shouldn't. Essentially the "train with 100% intensity" aspect is something that trainers and coaches should monitor with their athletes.
Trying to hit a PR every day would be similar to a 100m sprinter running themselves into the ground trying to hit a new 100m PR time everyday, or a running back and a linebacker hitting each other at full speed every day. Its not practical, and there’s no purpose to it. Its actually detrimental to your long term progress.
It boils down to this.
Train smart. Then train hard.