Reposts do add value though. Think of it this way: there’s a pool of content you haven’t seen before and a subset of it which you’d enjoy seeing. If no one reposts anything ever, you won’t be able to see any of it.
In fact, some of the things you have seen before you would probably not mind seeing again. Maybe you didn’t think to save it at the time or maybe your circumstances have changed.
Anyways, I wouldn’t confuse low effort with low value.