It's a "horses for courses" thing as we say.. not sure if that's a US saying as well, but it means different people like diffferent things - obvious I suppose but it is surely the person who seeks to put us down showing their insecurity, and not actually anything that needs to be justified on our part. Maybe the guy with his .17 HMR at the range looks at your rifle, and he doesn't have any frame of reference for it, perhaps he finds it challenging that you have made such different choices to him and it makes him a bit uncomfortable... Now the mature person's response is to seek to understand to further their knowledge and experience etc, the childish one is to try and go one up or put you one down: "it's a toy".. basically mine's bigger than yours. Pity the fool!
Then shoot him in the leg.
When he's recovered from that, set up a course of targets at unspecified random ranges from 10yrds to 100yds or whatever and both shoot them with both rifles. This will show you why the airgun potentially makes you a better shooter because you will likely be more familiar with projectile trajecory and better at estimating range because we have to be with airguns. HMR is impressive and efficient but it is point and shoot!
A good friend of mine calls me a "librarian" (sorry to any genuine library workers on the forum) for liking ariguns and precision shooting etc because when we're at the range he gets out something lound and military looking and empties magazines in the general direction of a target. That is fine with me! in fact it is awesome but it is different gravy.