It's not that keeping in touch is in itself wrong; it's that keeping in touch has to be a two-sided process. If one person isn't interested, then the effort will fail no matter how assiduously the other party tries to keep in touch. So it's pointless to keep reaching out if someone consistently fails to respond.

The first comment is not about someone who tries to keep in touch long after the other party has lost interest. It's about being bad at keeping in touch at all, even if the other party is clearly very interested in hearing from her. It's basically the opposite of what the post is about, so I don't see why you're confused.