I think it's absolutely true - Evan tells more (and more detailed) lies in an effort to maintain the fiction. BUT, because of those lies, his school (at least as reported by Alana) rallies around Evan and becomes less "clique-y." In addition, we see and hear comments from many people who seem inspired by Evan's speech and The Connor Project.
As far as the "odd slant" goes, we are all certainly welcome to our opinions, but I think it's an interesting question - can bad actions bring about good results? Does the large scale good done (thousands or millions of people inspired and perhaps moved to action in their own communities) outweigh the localized, small-scale pain from Evan's lies, which he told with good intentions? I'm not coming down on one side or the other, I just think it's an interesting issue that the show raises.