Perhaps...but this has been my observation recently. A persons ideological position is always used as a gauge to judge the quality/value of his opinion on a par

Perhaps...but this has been my observation recently. A persons ideological position is always used as a gauge to judge the quality/value of his opinion on a particular topic. If a person is of/ perceived to be of an ideological disposition different then mine and then whatever he or she says gets discounted. Your argument about people being Bayesian assume that they are rational. In practice, you find people sticking to their prior beliefs even more strongly even when the evidence to contrary is stronge, so called backfire effect. In fact, a lot of people reject the evidence simply based on the Ideological disposition of the source that it comes from and terming it as XX wing conspiracy.