I'm not sure how a term used to refer to a online PC since the 90's has become derogatory.
If someone has an issue with "toon" I would assume they are newish to the MMO genre.
If someone would use avatar to describe their character I would probably go into a laughing fit.

It's strange how language changes though.
I remember after leaving EQ saying to a group I was gtg after a brief afk. They all got pissed off at me and I realized that outside of EQ gtg doesn't mean "good to go" after a afk return.

As for the OP, you probably just saw a multi-box RMT farmer.