Because I thought it was funny that the seesaw didn't move. I can move a bus just by walking into it but I can't move a seesaw.
I laugh every time my character walks about without rocks and stuff tumbling around
I laugh every time my character walks into a wall and it doesn't say bong or bump
I laugh every time my character throws a glass bottle and it doesn't break
I laugh every time my character shoots a missile at a freezer and nothing happens
then again it was never funny, it's just what happens in an amazing game not meant to give a stuffe about seesaws.