When a lefty says anything about having the *right* not to have religion *forced* upon them, what they mean is you don't have the *right* to freedom of speech or religion because they don't approve.
Their *rights* always include the violation of the rights of another.
Not sure if you'd consider me a 'lefty' or not, but when I say it I mean that the government doesn't have any business - ie is constitutionally prohibited from - passing laws or implementing policy that either promotes or discourages religious beliefs.
It's fine, for example, if you want to take the day off on Sunday for worship, but don't make laws telling the rest of us we must do likewise.
who's trying to?
None that I know of. I think most states have repealed "blue laws". That was an obvious example of what I'm talking about when I say I we have the right not to have religion forced on us. There are plenty of less obvious examples - situations where taxpayer money is spent benefiting or promoting religion, or where tax policy benefits religious institutions.