Because your friends are used to seeing you a certain way. They prefer to see you where you’re currently at instead of where you’re going so they don’t have to keep up. Strangers have no idea of the old you, so they can appreciate what you’re doing now

A lot of who people think are friends are really just acquaintances who filled a role at a point in time but are now just distant observers on social media. The strangers who syooort others are likely attentive and empathetic in general.