I guess that under certain circumstances INFJs can get extremely misanthropic. I've been there and done that. So many bad things happened at the same time, not so much to me, but mostly to people close to me, and that had an enormous impact on me, it crushed me to the core, that quantity of negative emotions which I tend to absorb, led me to a place where I started examining my views of the world and people in general, and I believed that from then on it would be much easier for me to expect nothing but bad from people and to believe that people are generally driven by bad intentions. That much hatred made me more miserable then I was when I was just disappointed at people. This was sad, sad period for me, and I don't like to remember myself as I was back then at all.
I believe that people are mostly good at their hearts, and recognizing that I can't function believing otherwise got me out of that sad place. Now I know that from time to time I'll inevitably get disappointed and I've accepted that. I think it's better for me to be what I am, than to live as miserable, cynical and misanthropic person.