This is probably said by people who go to church but I don't know.
You can just say Happy Easter, but this is generally not practiced unless you're with people you know.
For example, I live in a city where the population is over 50% immigrants from all over the world. One would assume that a huge segment of population is not Christian (be they atheist or of some other religious persuasion). It's considered polite to avoid religion-specific greetings, however upset some Christians might get.*
*This message is for education purposes only.