It's nice having the message because first-timers don't always let you know it's their first time, something possibly warranted given how caustic this community can be. That said, it's nice to know when someone doesn't know what to do on a fight that takes coordination. For example, I did an HM Ifrit run where one of the two tanks had no clue either how to MT or how to stun, and didn't let anyone know. It led to some problems that could have been easily avoided.

When people react poorly to it being someone's first time, that's on them. But when you don't let any of your 7 party members know that you don't know what's going on, it's disrespectful, and that's on you. (I probably sound bitter, because I am - I'm a DPS. I hate waiting in queue for 35m only to have things fall apart within the first few minutes because of things like this.)