To me it seems like the Vatican is finally catching up; there probably has been life on Mars, a very close planet, and we're about to be sure about
that (the Mars lander has found something that might be ice) - there's really no denying the possibility of other life in the universe now. So
before people can start questioning the Vatican ('but we were never told this, what else dont we know?' and such), they cover theirselves.
Well, that might just be my paranoid opinion

but in any case, I really like your hypothesis! As you might've guessed, I'm not a religious person,
but I feel like religious persons might like this as well. Finally, a subordinate goal!
At least when not everyone thinks Satan is behind other life.. really can't reply to that