'What is truth'?
Your assumption seems to be that there is no objective truth, or at least that no one can know it, and that no one should be claiming that they know the truth and that all of creation is subject to that truth.
I think that you are wrong. There is a God who created everything out of nothing. He *is* Truth. He made covenants with His people, and became man to redeem man after man had rebelled against Him, like the fallen angels, aka devils.
His law is written on man's heart, but because of the effects of the rebellion and sin people have a propensity to not recognize it or to ignore it. That is why there is a tendency for many people in other cultures to naturally know right from wrong in at least many respects. It is also why people and societies tend to stray from what is right and to devolve into evil.
"Thou shalt not kill..." meant thou shalt not kill the innocent. It could be a long and involved discussion, suitable perhaps for another thread, but there are exceptions, much like there are exceptions in modern law. People have a right to defend themselves, of course, with limitations.
"it's when you believe your belief is superior and therefore have the right and obligation to impose yours on me, which is what the religious right believes."
Again, I think you too have such beliefs, though yours undoubtedly differ from mine. You are not an anarchist, are you? I'm guessing that you would want to impose your beliefs on some of the Muslims who have beliefs different than yours. For example, a man, his wife & other children felt that a daughter who had become too Americanized in dressing immodestly deserved to die. In fact, they felt that their religion required an "honor killing" to restore the family name, and in fact they did stab her to death.
https://fox2now.com/news/true-crime/die-my-daughter-die-1989-honor-killing-shocks-st-louis/
Do you think that your beliefs are superior to theirs? Would you want to impose your moral beliefs on them?
There are numerous other examples, of course, from arresting drunk drivers, or people who felt they needed to kill or injure someone for disrespecting them. Ditto for people who felt that they deserved to take someone else's money or property because life wasn't fair and they deserved it. Or do you really think that no one should impose their own morals on anyone else?