There's just a fine line between explaining to someone that this is a hard training ride, we work to keep in a fast paceline, maybe you should try Wednesday nights first, etc., and just being hostile toward a rider who, I'm sure, doesn't know any better. The latter is one of the reasons people think of road biking as an "elitist" sport.
I will still argue, at the risk of splitting hairs, "NOT to have to deal with you" and "I need to train at the highest level possible" is a statement that arises from a big ego. You're a good rider. You'd drop me like a hot rock. But let's face it--not having the time to show a noob what's up because you "need to train at the highest level possible" is a function of ego. I'm not even necessarily calling it bad, but there IS an inherent "I'm better than you" in that statement.
One of the reasons that I do most of my riding solo is that the A/AA riders in the local club have no time for anyone that isn't a regular or might be trying the paceline thing for the first time. I'm fairly experienced at packs/pacelines, and I've started racing Cat 5, but the attitude that newer riders get from you and others on your Tuesday night ride are what turn them off to cycling and never give them the opportunity to develop their skills.
At least tell folks how it is and offer the option of the Wednesday night ride. Just don't slam the door on an up-and-coming rider just because they might drop your HR for a minute or two during your training ride. All I'm saying is that a little consideration and courtesy can make or break the experience for a newer cyclist--Believe me, it takes some courage just to show up at a fast club ride the first time. Why not be a little more welcoming and make the rider want to come back for more?
DrPete