For me, I don't think you have to agree with a post to learn something from it. So I hope you would say what you think.
You will never know how many people benefit because for the most part, those who disagree seem to be much more motivated to post than those who agree
I don't think you should try to filter what you say according to what you think people want to hear (apart from personal attacks obviously) The filter should reside in the reader. It is not compulsory to read anything you are not interested in.