This fella who drafts you, do meet him often? Do you know his name?
I remember when I was just starting out on bicycles and I started riding with a club. (Covina Cycle Club, Southern California) There were three distinct groups. The Racers, slender guys with their sleek bikes. There were the core clubbers, always fun to ride with, and then the newbies like me.
The Racers would meet at the same time and place as the rest but usually dash off on some 60-120 mile ride they cooked up among themselves. They were COOL and I so admired them.
The newbies would take a short route to the food stop of the club ride until we were strong enough to do the whole ride. Newbies always had an experienced rider along to give tips and encouragement. I always felt welcome.
As soon as I was able to do the full club rides (20-40 miles) I found out that there was ALWAYS one or two Racers who came with us. They would rotate the "duty" of encouraging newbies like me. The result was that by the next year, I was riding with the Racers and encouraging newbies myself!
My point is, when I was new to the sport, you roadies were like the gods! You lived in a world that was beyond what I could ever hope to do. My continued interest in cycling today has a lot to do with six or seven guys that took some time to encourage me and let me be a part of their world. They are true ambassadors of our sport.
All of us started at the same place- we all had to learn to ride a bike after all! For the sake of our sport, let's encourage those who draft us! A few friendly words like; "If you keep hammering like you are today, I'll be trying to keep up with you!" Or when you come up on that dude on the MYB; "Gee you were hard to catch! Do you do a lot of riding?" It will cost you very little, but it may pay big dividends. After all, you are going to need someone to buy your old bike from you when you upgrade!