Well, there was another point to my comment: that criticism of Hebikawa tends to paint her as much worse than she really is. That realistically speaking, it's far more likely for her to be portrayed sympathetically by this very manga (not just by fans) when truly bad things happen. Case in point, the aforementioned creepy ex.
All her evil acts (badmouthing people behind their backs, thinking ill of others, pretending to be friendly, teasing rivals, etc.) aren't particularly vile and are kept at harmless romcom levels. In fact, she's been a victim of far more serious evil herself. Is she a bad person? Yes, she is, but hardly irredeemable. It helps that she isn't friends with Kusunoki or Moe, so it's not as if she has a moral duty to put their feelings above her personal interest, and she's actually trying to be nice to Shuzuki in her own way.