> There's something odd that's happened, where opinion and niceness has become sacrosanct, beyond truth.

That could be an adaptation to the information (and globalisation) age. Since you're more likely to meet with more (and more different) opinions and have no way of instantly checking the facts behind them ,with the sea of information available, you have to first be nice. You are forced to accept the possibility that your opinion might be wrong because you can not possibly have access to all of the facts.