I can’t judge anyone who does not keep the Torah. I know three siblings who survived the Holocaust together- one stayed frum completely, one went completely off the derech, and one initially went off but later came back and raised his family in a Torah lifestyle. From very similar experiences each derived completely different points of view and very dissimilar reactions. Each made their decisions based on themselves, and as I have no window into the thought process of another person, I therefore cannot judge to know WHY and therefore to condemn, as condemnation can come only from my context.
That said, as has been mentioned, the words “superior” and “inferior” really have no place in this discussion. The word “superior” as applied to oneself, especially when associated with the word “inferior” when it’s applied to others, is really against the whole idea of anavah and not trusting oneself until the day of one’s death. I think that a much better way of looking at it is by seeing if you feel like you are doing ratzon Hashem. If you feel good about doing Hashem’s will then you will feel good about the fact that you do so and, thus, about yourself. However, you, in relation to a nonobservant Jew, are not inherently superior in the traditional meaning of the word for a whole slew of reasons- among them being that nobody is judged in comparison to others. It seems more appropriate to wish that the other person had the same sense of hana’ah and fulfillment from doing ratzon Hashem as you have- the idea behind kiruv. It’s like the difference between kinas sofrim and regular kinah- one is constructive and one only destroys.
In summation, I don’t think anyone can look down on a nonobservant Jew as inferior (as in, oh, I should cut you in line because I’m just a better person). Luckier, perhaps, but not necessarily better. Not until 120 will we find out how Hashem does his din v’cheshbon.