Gavra, first of all, I said “some cases”. Yes, there is a difference between cases in which there is a valid shittah, and cases in which there isn’t.
But I don’t think being smug ever has a place. Should I feel superior compared to a mechallel Shabbos? I think not, yet I’m sure you’ll agree that I shouldn’t feel like what they’re doing is perfectly fine.
That having been said, I think there are certain “chumros” which should be considered inherently better.
So I can give you several halachic arguments* why one should be makpid on Cholov Yisroel, yet understand that there is a shittah to be meikil, and, in fact not mock someone who eats actual tarfus (unless specific circumstances dictate that “leitzsnusa d’avodah zarah” is in order).
*I’d be more than happy to take that to another thread, if you’d like.