Power-leveling is absolutely BROKEN

[Issac]

But the entire point is to use power leveling to get your friend to endgame quickly so they don't get bored / feel left out wallowing at low levels by themselves.

However, you don't have to be powerleveled. If the journey to 50 is more your thing, then take the time to enjoy it. There's no pressure to get powerleveled at all unless it's for the express intended purpose which is to get into endgame content faster.

So, to sum up, if you care about endgame, you can get there faster through powerleveling. If you care about leveling at your own pace without any help, then don't get powerleveled and enjoy the existing low level content at your leisure. If one of these options isn't fun for you, then don't do it. It's a game. Have fun with it.

I have to do this again?

You can progress your character by leveling slow.

You can progress your character by leveling fast.

Choose the way you enjoy.

You can choose to get mad at the plvl killing all your mobs while you're trying to have a legitimate party.
Edit; Yes, it has already happened to me. Few hours ago.

You can choose to give up and get a plvl.

Or, you can choose to help send the message that this needs to be fixed.