How does SE justify these ten min enrages, but doesnt let anyone know their dps

[Reynhart]

So are leechers and special snow flakes begging for carries.

Easy fix. Make killing the training dummy mandatory for entering the corresponding content.

It's not knowing if you're "good" or "bad," but if your performance is up to what you either 1. seem to think it is, or 2. what you would like it to be. This game doesn't provide any way of knowing either of those.

Yes, it does. It's, again, called training dummies. Instead of measuring numbers, people can measure how fast they kill it. What's best is that if you can kill it, whatever time remains, it means you do enough DPS, and you shouldn't care if people try to harass you into doing much more just because they have stupidly high standards.