If you're new to a place, it's best to hang around (called "lurking") and read a while before jumping in and telling people how they should behave. That's pretty basic. I was protesting the arrival and disruption of our ongoing banter by someone virtually standing in the middle of the room and changing the subject by announcing they had arrived without a clue as to where they had arrived.

This kind of behavior can set off Gluon or the freds and then you're not only likely to lose Pluto, you're liable to have someone pack it up and carry it off or send it careening into the moon. So be careful where you step and take your time introducing yourself. That's not so difficult.