I think my 99 year old friend Dave sits on the bench a lot.
Do you think sitting on a bench is bad?
I think he's just crazy for wanting to do it so much. Why would you do it so often?
Just because you don't understand why someone enjoys something doesn't mean it's bad. You shouldn't criticize someone else for doing something they enjoy, especially since it's doing no harm to anyone. You should be more open minded of what other people like.
But why would you enjoy sitting on a bench all day?
Maybe it's because he is 99. He's too old to move around like you so he enjoys sitting for a long time.