There's something broken here. I created a normal account from the
signup page and logged in, but I can't leave comments. I can log in, I can check out my settings and profile. But every time I view the
page of a suggestion, it acts as if I'm not logged in, even if I am. Going back to the
main page shows me as logged in. Thus, I simply have no way of commenting on suggestions.
EDIT: It turns out this is the only suggestion that seems to have this problem. Very weird.