I've figured out how we can make all the religious people and the non-religious people happy at the same time:

WE KILL ALL RELIGIOUS PEOPLE.

Here's my logic:

Regardless of what religion a person belongs to, they always believe that after they die, they are going to a place where they will have happiness for eternity. Streets made of gold, 76 virgins, or whatever their religion says they'll get when they croak.

So, if we kill all religious people, the religious people will get their eternal happiness, and the non-religious people won't have to listen to their crap anymore. It's a win-win situation for everybody.