I think there's a difference between noticing and judging. Noticing doesn't seem particularly unhealthy. It's little different, really, from noticing other cars with the same make and model as yours. It's human nature to look for "you" in other people and things.
Judging, on the other hand, is something that's under our conscious control. We can't train ourselves not to compare without a good deal of effort, but we can easily train ourselves not to judge. I've been guilty of a few more judgmental thoughts now than I used to have when I was at my biggest, but I give myself a mental smack-down when I think that way. Just because I've found my "magic pill" in the form of calorie-counting, exercise, and slow weight loss doesn't mean it's
everyone's magic pill or that everyone else who has extra weight is even looking for such a thing.
I don't know if the woman with a cart full of pizza bites and sacks of snack food is going to go home and indulge in orgiastic consumption alone or if she's buying for a party or if she plans to donate the stuff to her local church group. I don't know if someone is in a cart because she's fat or got fat because she's in a cart, so how would I presume to judge her?
With that said, you shouldn't feel bad for your thoughts--instead, try to understand why you think differently than you once might have thought. Some former smokers, for instance, become
rabidly anti-smoking to the point that they treat smokers like sub-human crap; I'm convinced that it's self-loathing they're expressing. (And I'm a former smoker myself, although I don't treat anyone like sub-human crap.
)
If you find yourself thinking, "Aaaaaand THAT is why you're fat!" a lot, maybe it's a thought you need to think to remind yourself to stay with your plan. Maybe your judgement helps you distance yourself from your former self. Maybe it helps you draw a thick dark line between acceptable and unacceptable behavior for yourself.
I try not to judge--and that includes not judging judgers. It's whether you ACT on that judgement and say cruel things to people out loud or give them dirty looks that matters. As long as you're not going around grabbing junk foods out of people's baskets or causing a ruckus at the family dinner table, I don't think you're doing anything wrong.