Let's paint a little picture.
It's spring 2002. At 1200h GMT a radio and TV announcement is broadcast on almost all conventional frequencies, in appropriate formats according to the medium and the area.
It's from a bunch of pale violet humaniods who have come "In peace for all Qw'z'x>kind". They say they want to meet up with the UN in full cnongress.
Disbelief rapidly turns to amasement when CNN and other news-services provide footage of a large alien vessel descending into the river near the UN. Large in this case means 5km long... and wisely, none of the SAC jets sent to have a look pull a Will Smith or anything stupid, although one gets nudgeed gently away by an invisable beam of some sort when it gets too close.
Let's say it becomes apparent the aliens are utter benign, happy to hand out technological aid, scientific knowledge, and hope to welcome the people of earth to your typical peaceful federation of planets (about 5,00 different species all told).
How do you think people would react? How would religious people react? What if they greet enquiries as to the existence of god with a cough and a polite smile, and a comment along the lines of 'well, we believed that sort of thing 2,000 year ago, there's no need to be embaressed, it's a natural part of a societies development'?
People living in glass paradigms shouldn't throw stones...