Time was when the less faithful would at least tolerate those who had faith. That day has passed. Today the faithless have just as much animosity towards those who have faith as the faithful have towards the faithless. Indeed one reason for our highly polarized political life is that the animosity of the faithful, who are mostly Republicans is returned at full strength by the faithless, who are mostly Democrats. How did we come to this point?
911 for one thing. On September 11, 2001 we all watched in horror as the towers of the World Trade Center came down. They were brought down by men who acted in the name of Allah. Now some people blame Islam for this event. But some go farther and blame the idea of faith for it. The event itself was evil. It was done in the name of God. It was done by men who could never be convinced God did not endorse it. So we must conclude either God is evil or the men who were behind 911 are deluded fools. Either way faith has been exposed as wishful thinking. Dangerous wishful thinking. 911 the best advertisement atheism has ever had.
The question here involves the certainty of knowledge. Faith creates the illusion we have certainty of knowledge. But in reality there is no such thing as certainty of knowledge. All wise persons live with some degree of doubt. Doubt simply reflects our realization there is in reality no such thing as certainty of knowledge. It is only through doubt in what we presently know that we can grow in wisdom and knowledge. If we do not doubt we can never become wise. But doubt is not popular. Through faith we can rid ourselves of doubt. But in ridding ourselves of doubt we replace reality with illusion. Since we are no longer able to question our view of reality we cannot know when it is in error. Eventually reality retaliates against those who ignore it. And people of faith are always ignoring reality. How could it be otherwise? Understanding reality as it is requires doubt. And the purpose of faith is to eliminate doubt.
So here is one reason for the existing animosity to religion. Believing in any religion requires faith. Which means belief in any religion brings to the believer all the disadvantages of faith.
The faithful become arrogant. The faithful come to believe the holiest of ends justify the vilest of means. And those who disagree with them come to act the same. How could they not?