Well, no. Just no, there's nothing wrong with ppl measuring thier PvE performance when thier role is to DPS. It should be just like it's in FFXIV, DPS Meters are not officialy approved, but as long as you keep it for yourself while in public group you're in no danger of being banned or anything, but if you're going to be toxic and abusive cause player X does low DPS in your opinion and then harass him/kick him from the group - that's another story and such behaviors should be punished. Remember that DPS meter is just a tool to measure your damage output, nothing more, nothing less but how people use it may lead to toxic behavior.