For some reason, bike shops can have this whole "If you didn't buy it from me, it must be crap" mentality.
Yeah - I did think of the Ford-Chevy analogy. Also, the cliche "Opinions are like belly buttons. Everybody's got one."
You did your research. You made a sound, reasoned decision. He doesn't have to like it, but it would have been nice of him to keep his yap shut. An offer to service is legitimate - but an "if you have problems" vs. "when you have problems" would have been a little better.