I'd also suggest encouraging your regulars not to engage any of the trolls that enter your room and to ignore them.
Literally ignore them; it's a feature that members have and should take advantage of. They can right click a member's name, either on the room list or in chat, hit 'Ignore' on the popup and
presto! - they're rendered mute for that member. I've put so many undesirables on ignore for being abusive, disrespectful, racist, mean or just for general jackassery. Even for excessive whining, which is a pet peeve of mine. Members will still see an ignored member in the room list, but the ignored user's name will be highlighted in a reddish bar.
I point this out because some members or visitors to your room, especially members who may be newer to MFC, may be unaware of the functionality. They just have to hit that blue 'x' and the offending member is now muted for them. They can also manage the ignore list from their personal options.
Room regulars who genuinely appreciate the time they spend talking to you in your room, watching shows, laughing with other regulars... they will often feel the urge to confront some of the dickishness a new troll can bring. Please remember that this is
not them believing that you can't stick up for yourself (forgive me, for lack of a better term) so much as it is them disliking a troublemaker causing a scene in one of their favorite hangouts and voicing their disapproval of said behavior. Think of it as someone from out of town coming into your favorite bar and badmouthing the favorite bartender or owner. People will naturally take offense to that kind of thing. Your room regulars are no different. Just encourage them not to engage (because that often makes it worse and feeds an asshole's ego) and to just ignore anyone being an asshat until you can ban them.
I swear, my ignore list
must be the size of the U.S. tax code. Seriously, it would choke a spreadsheet.