You're making the assumption that Ballmer even knew about this, which isn't immediately clear. Someone at Microsoft certainly did, but so did people working within the government. You know, people working for US citizens, ultimately, if you still believe in the whole "government for the people, by the people" thing. So far, only Snowden leaked any of this stuff. I think it's unfair to lay the blame at Ballmer's feet in particular, considering both of those things.