Goodbye USED TO mean "God be with ye". However nowadays it's just a farewell phrase. Anyone can use it regardless of religion. I'm sorry, you've really read too much into that old meaning. :) Also, I'm pretty sure no-one has stopped using "sunrise" and "sunset" since the discovery that it's the Earth that moves, not the sun... ;)

GOD HAS ALSO NO RELIGION......... like you.. RELIGION IS MADE BY MAN NOT BY GOD. So you are free to say Good bye to anyone.

Goodbye hasn't correlatives with religion, that word you say into your friends or someone else when you want to go to another place,or after your finishing your conversation

Long live peachy.