1. Content creators get paid to play the game by their viewers, while most others have to go to work.
2. In order to serve their "customers", they often no life content at release. This is how the world economy works.
3. Their viewers help them in many cases. This is brand loyalty, the mutual loyalty created by both sides.
4. You'd do all that too if you were in their position because it's logical.

In this case, the entrance issues affect everyone. It's problematic for just entering it as a coordinated group. Non-coordinated groups are likely to have a mistake that wipes everyone. So SE is to blame for requiring the participants to not make mistakes. If it was like CEs, discords wouldn't matter for it.

It's not just content creators who necessarily have to wait for the majority to reach max level and grind gear/buffs, it's no-lifer types in general that complain about that. It's also kinda logical that this issue happens though because most people play casually.