Is it because we haven't figured out how the death traps work?

Well, there are good ETs who know more, so...

Is it because the good ETs don't know how to deactivate the death traps?

Nah, they know how.

So, what's the reason to not deactivate the death traps? Is it because the good ETs want to avoid the war?

Nope, they would win.

So, what's hindering them?