I have to agree with this one; deleting it totally and leaving it for beginners isn't a smart idea because not everyone is bothered by the same message as you; perhaps some people need a reminder like that.
Well, in a previous reply above I mentioned that I thought about suggesting a setting instead of this one. But the reason I changed my mind is simply we've been here for so many years and we are already done with all the server stuff and how things really work in game.
Also the list of settings in the '/settings' GUI is crowded enough to add more in it.
And again, it's as always up to developers to choose the best option for the community to rather make a setting for this or just limit it to new players only.
I wish you all a good day