When I hear that people should not impose their 'religious' beliefs on others, I always wonder what qualifies as a religious belief as opposed to just a belief, Period.
For instance, take something as simple as the Ten Commandments
stealing is a crime
killing is a crime
perjury is a crime
and adultery is grounds for divorce
were these 'religious' beliefs that were 'imposed' upon others?
where do people draw the line to determine when a value or standard is 'religious' ?
why are some standards accepted culturally and others seperated as merely 'religious'?
I think you have some things mixed up here.
First off, because many religions did start out as attempts at government, there are lots of items which are laws in secular societies, which are also laws in religious societies. That isn't because religious ideas were imposed on others, it is because governing a society of any kind, is likely to include lots of similar basic rules (also, if you read enough history of government, you will find that SOME governments evolved from being nominally entirely religious, first to being both secular and religious, and then to being entirely secular). Simply, it is considered a "bad thing" to commit murder, according to the ten commandments, and it is ALSO considered a "bad thing" by our secular government.
Next, the big problem with having laws passed BECAUSE they are dictated by religious beliefs, or even have the APPEARANCE that they are dictated by religious belief, is that that act puts that religion into competitive authority with the rest of the government.
What's the difference between a religious belief and a non-religious belief? That can seem subtle, but not because it actually is, rather because a fair number of people don't think things through. There's not much difference between "I just KNOW it," and "I know what God wants," and "I read it in an official religious text." But there is a HUGE difference between those, and "I believe it is necessary to an orderly and peaceful society to declare certain actions to be illegal." Translation: lots of people use the word "believe" interchangeably with the idea "logically reasoned through." And others who are a bit on the sneaky end of things, will purposely pretend that there IS no difference between those definitions.
Now. One area where things get VERY difficult to sort out, is where we try to figure out how to have FREE EXERCISE OF RELIGION, without that meaning that people who are religious are allowed to do things their religions dictate, which involve altering the course of other peoples' lives who may not have the same beliefs. We've had fights over whether SOME religious people should be allowed to discriminate against people who didn't believe as they do. Some Christians think that's great, when it's Christians who are doing the discriminating, but some Christians think the same idea is terrible if they are the ones BEING discriminated against.
Basically, when you're on the receiving end of a privilege, it can seem to be a very good idea; but when you are on the other end of things, not so much.