Re: Judgement Day
"You know, when thinking about it it struck me as odd that postponing Judgement day was seen as a good thing"
They also assume that what they're doing is a positive thing. In their existing timeline, the human race exists (barely) - who's to say that it would exist at all when they meddle with it?
It's like the argument over whether you would kill Hitler by time travel - Hitler lost the war and was an atrocious war tactician. Would you really want someone better skilled to take his place?