Or maybe you have come to identify validation of grief with its sacralization, and you don't accept someone saying at the same time "I understand you, it has happened to me as well" and "it will pass, there is a bigger picture in which this becomes less relevant".
> Commonality does not make negative emotions less terrible.
There is a saying in Italy: "a shared misfortune is half a joy".
There's a recognized therapeutic value in literature. Reading novels doesn't validate your emotions- reading is unidirectional, there is nobody telling you "I understand you" from the pages of a novel. But you get in contact with characters who suffer, confront problems, overcome them or succumb to them. You can see their inner life, and recognize a commonality of human experience.
Conversely, social media are notorious for making people depressed: it can be as unidirectional as reading, but since people tend to show only the positive aspects of their life, it can make you feel your own life is especially bad.