Contrary to all-too-popular opinion, being dan li’kaf zechus applies to those who are more machmir than you just as much as it applies to any other Jew”
It is unrealistic to think that people who are machmir (when solely halachically-speaking they have no reason to be), do not think they are just that little bit more frum. They do, and blind refusal to acknowledge that fact, is a little naive. And yes, I am personally dan l’kaf zechus on my more machmir friends in MANY ways, but I have heard enough judgmental comments come out of their mouths regarding people whom they deem to be less frum than they, to make me realize that this is so. And that is no sweeping generalization. However, I also acknowledge that your experience may vastly differ from mine, thus your own observations reach a different conclusion.