Even the religious Zealots would clam up for at least a day.
Actually, the exact opposite would happen.
Everyone who fears their power might be fading due to this occurrence
would attempt to 'get ahead of it' and point to the exact passages in
their book which would maximize their historical power in light
of this new event.
No matter how 'pleasant and reasonable' the 'aliens' were (I'm not
saying they would or would not in fact be aliens, that is not the point),
the cries of the 'real significance' the 'hidden evil' being covered over,
and what not, would not decrease in volume one tiny bit... it would
in fact increase in volume ten-fold.
Said 'aliens' could cure all diseases and give every person alive a
'scientific device' (say a star trek replicator) which met all their
human needs for free.
And these 'aliens' would be cast in the most evil light, by a large
percentage of the human populace.
It seems that the great majority of humans believe in evil (it seems..
I can't quantify.. but most major religions are full of teachings about
'evil') and they will not be denied!
In fact a lot of people seem to be trying to blow up the entire world,
just to PROVE that supernatural evil exists. The truth of the matter
is that THEY ARE the supernatural evil in a sense.
This is my take on it.