The problem with you is not your philosophy, it is your attitude.
Let's rephrase the argument:
I despise modern art. I find it to be utter, utter crap. Blobs of color that a 3 year old could paint if they had no taste. However, there are people willing to waste literally millions of dollars on it. There are two approaches I can take to this.
One, I can not go to Modern Art galleries, not purchase modern art, and generally avoid it. This is called "consumer choice" and is the mature approach to the situation.
Or, two, I can go to galleries, berate people to their faces and call them morons, throw feces and urine on their most respected pieces of "art", and petition the government to remove all modern art from all government places, and sue if they won't comply. This is called, "Douche-baggery" and is the choice you and many other atheists and atheist groups have made.
If anyone gets in your face, it's because of your attitude.
Yes, there are a lot of deluded people in the world, but pointing out their delusion does not endear you to them. Don't believe me? Try pointing out to a group of programmers which editor is better, vi or emacs, spaces or tabs, or C++ vs. Java.
And, by the way, the biggest delusion anyone has is that they know the absolute truth and are totally right in any situation, on any social topic.