You are being a dick by implying that wanting to concentrate on racing is rude.
You obviously lack league experience, so you should know a thing or two.
It is common knowledge in a lot of the leagues, especially in endurance events, that chat is either disallowed or strongly discouraged, and only allowed to notify the admins.
And blocking the messages is not an option. The In-game chat is extremely disturbing, especially when you are concentrating, and not there to fool about, but to give your best in the team effort. Therefore it is common, that messages aren't blocked in events, so the admins could get messages through at the drivers when needed.
Saying that 2-4 lines every 75 minutes is nothing, (even if it says affermative, gay pidgeon) is just showing that you either don't know a thing about league based racing, or you are just blatantly ignorant, not having any respect towards the rest on the track.
If you can't hook up a TS/Ventrilo/Skype conversation or simply a third person to communicate with the others during the race, then you are in the wrong place, and should look for pick-up or non-team-based action.
common sense in LFS, really.