I don't think INTP are naturally accepting. I think we are bad seeing points of views that differ from our own. One thing is the exploring phase, when you are still searching for "the truth". This is the Ne phase, we could say. But once we settle on a certain truth or philosophy, we tend to percieve everyone else as wrong. The catch is that once our philosphy changes over time, it is very embarassing to look back and see how judgemental we were to others.
It's like someone who just read Marx and suddenly percieves everyone who has a normal job and isn't a radical leftis as a capitalist pig. That's INTP at their worst.
Thankfully, the intellectual honesty makes us constantly re-evaluate our beliefs so that over time they become more balanced and comprehansive. INTP perhaps benefits from aging more than any other type.
That's my experience.