Re: everybody has their own opinion.
I'm not sure, but you seem to be saying that if things are ultimately matters of opinion, and are all open to interpretation and challenge, there's no point in arguing over them. But we can still agree somehow. Consider the reverse: It is over matters of fact, that arguing is pointless. If something is true, all that remains, is to accept it. But opinions are not whims, they are beliefs. And it is over just such opinions that it is worth arguing.
Also, is everybodies opinion their own? Are people's general beliefs carefully and critcally come by, or are they just beliefs they've internalised
without much thought from their culture?