Tsunenori:

This is 95% of my issue with it.
I couldn't care any less about anyone's, including my own, xp gain rate. Call me old school, but I grew up (I literally grew up) playing FFXI from launch until around 2010/11. I was ok with slowly leveling in Valkurm Dunes. I even remember trying to reach the old level cap in Bibiki Bay fighting Dhalmel. So leveling slowly is just part of a FF game to me.
What I do care about is common courtesy and decency. If I see a group of other people working together to accomplish something constructive, like xping, I'm not going to go over and ruin it. Also, if someone ruins my opportunity out of ignorance, I'm not going to yell at them. Both sides could use more patience with, and consideration for, the other.
The other 5% of my issue is with SE's silence on whether or not this is working as intended. That silence has contributed its share to the behavior as its enabled both sides to feel they're right and the other is full idiots.