Your messages were flagged as offensive by 11 users and counter-flagged by 5 users. With the 11th flag, the difference between flags and counter-flags reached the threshold of six, causing automatic deletion.
I've looked at the data, and here's something interesting: Out of the 11 flags, 4 came from people who were in the room at the time. None of the counter-flags came from people who were in the room.
So counting only people in the room, the votes were 4:0 for offensive. Thus assuming flagging was kept on a per-room basis, the same thing would have happened (since in that case, the threshold would obviously be lower).
There is no evidence at all that
The existing flagging system is known to be quite broken
as DeadMG says. This claim is regularly made by a particular group of people who, let's say, tend to be very liberal in their choice of words, and who think that in their room, they should be allowed to curse as much as they want. Of course the Q*Bert rule holds in chat as well, but not everyone accepts that.
Looking at the recent flags, those messages that were deleted due to reaching the threshold should have been deleted, and those messages that were flagged but shouldn't have been deleted weren't, because they were quickly counter-flagged. This includes the flagging troll in the C# room that you mentioned – those flags were gone pretty quick. Unlike with your messages, nobody agreed that they were offensive (because they obviously weren't), and so nothing happened.
popular Lounge<C++> opinion, the data clearly says the system is working remarkably well. That's not to say it's perfect of course, nothing is. But the oft-repeated claim the chat flagging system is horribly broken and needs to be fixed ASAP is entirely unfounded.
And finally coming back to your particular case, cHao says it well:
To be fair, though, in this case you did take it upon yourself to test the limits -- knowing full well that a bunch of flags were flying around. It's not like this was really out of nowhere.