Maybe they're prospecting for cream cheese ?
 
Seriously though, I was also wtf ?? when I first read about this. But since then, I also read that it's not a two ton bomb 
per se but rather they're ditching the rocket unit. this will 
have the effect of a small bomb. Still pretty careless if you ask me. But they're treating it as an opportunity to kill two birds with one stone:
1) What to do with Space Litter 
2) Year 1 Science Project
I read elsewhere that when they did something similar a while back, the 'moon rang like a bell for half an hour'... leading to thoughts that the moon is hollow.
So it will be 
just great if this thing punctures a hole in the moon and it goes whizzing off into space like a child's balloon.
 
Then what will we have to look at ??