I didn't know about Popper before. This rings so true today more than ever. I often joke about my home town of San Francisco that we are very open minded as long as you believe exactly the same things we believe.

Unfortunately, everyone seems to be keen on justifying their own intolerance with the supposed intolerance of the other.

If all it takes people to be freely intolerant is to convince themselves that the object of their intolerance is intolerant too, intolerance spreads everywhere.