OK, well first you asked me to explain the standard on which I base my position on free speech. I said logical argument and didn't elaborate. But then you changed the parameters of your question and demanded an absolute inalienable standard. I'm not quite sure what you mean by that. That this standard cannot be refuted? I think that that would kinda miss the whole point of the logical argument.
Yes I do mean that the absolute standard cannot be refuted. Something is either right or wrong. Period. It has nothing to do with how anyone including myself thinks. If 7 billions humans believed rape was acceptable, rape would still be wrong. Wrong actions are intrinsically wrong, and people's opinions or feelings has nothing to do with it. Therefore, it's wrong to deny someone's freedom not because people say so, but rather it's wrong because
it is. But you can still question and doubt the absolute moral standard if wish, that's the beauty of freedom of thought and speech!
Rational inquiry is impossible without doubt. We will never arrive at the truth if we do not challenge our beliefs. Knowledge will not advance and ideas will not improve. That is the basic principle behind free speech. We need it in order to better understand the world, ourselves and our relationships with each other. If certain speech were forbidden we would be cut off from a fuller understanding of that topic. As John Stuart Mill argues, if every person but one believed the same thing, that one dissenter's opinion would be the most valuable of all. Right or wrong the dissenter will keep us questioning and make our understanding stronger.
To suggest that this rationale couldn't be refuted would undermine the logic of the rationale itself.
Basically, according to you we have freedom of speech because it's a logical argument and it's a recognized importance because we believe in the full marketplace of ideas. But so what? Let's say attitudes change and now the majority says they have a logical argument to ban free speech. How do you know they're wrong and you're right?
You would know because you would take the act of denying free speech and you would COMPARE it with the unchanging, absolute standard of right and wrong written on your heart. How do you know something is unjust unless you have some idea of what justice is? Just as it is for you to point out a crooked line, you would have to FIRST know what a straight line is. This is why human beings don't DETERMINE what is right and wrong but rather we DISCOVER what is right and wrong using the same, unchanging standard that's in all of us.
Without the absolute moral standard it would be impossible to detect what is right and wrong. When you make any moral judgment, whether claiming it's wrong to deny your free speech or denouncing the holocaust, you are in fact COMPARING the act to the absolute moral standard. You're saying "this line is crooked and I know it's crooked because I know what a straight line is".
Without the absolute moral standard there would be no way to measure moral differences. Without the absolute standard statements like "murder is evil" or "racism is wrong" or "you shouldn't abuse children" have no objective meaning. They're just someone's opinion, on par with "chocolate tastes better than vanilla".
Without the absolute moral standard there would be no grounds for human rights. For example, the American revolutionaries wrote in the declaration of independence "they are endowed by their Creator with certain unalienable rights". In other words, the founding fathers believed that human rights are God-given, and, as such, they are universal and absolute - they are the rights of all people, in all places, at all times, regardless of their nationality or religion. The founding fathers recognized that there was a higher authority - the "Creator" - to whom they could appeal to establish objective moral grounds for their independence. Had they begun the declaration with, "We hold these opinions as our own..." (rather than "self-evident" "truths") they wouldn't have
expressed an objective moral justification for their declaration of independence. It simply would have been their opinion against that of King George. So the American founders appealed to the "Creator" because they believed his moral law was the ultimate standard of right and wrong that would justify their cause.