I've always thought that gossip, whether true or false, can be equally harmful. I would need to ask my rabbi about this question of yours, or perhaps
@rosends might have an answer, as I know that he is a rabbi.
My own thought on this is that, even if the gossip is true and not intentionally harmful (such as: "I heard from Shayna that Zelda is expecting twins! Mazal Tovs will soon be due!"), it could be that the person who is the subject of even "good gossip" may not want to have her personal business discussed out of hand. And, if she were to discover that she had been the subject even of "good gossip," it might cause her undue anxiety that could lead to health issues.
This is only my own take on it, as a Jew who tries to be good but, admittedly, sometimes falls short of the mark.