Can people have a phobia of atheism?

I think so.

phobia: an exaggerated usually inexplicable and illogical fear of a particular object, class of objects, or situation

Crazy Christian Lady

Is it rational to fear certain practices such as magic, astrology, tarot cards? What is the harm? None. There is no harm from seeing a magic trick, looking at a horoscope, or shuffling tarot cards. Relying on that information would be a separate issue entirely, but the actual actions themselves are harmless. I think it is safe to say that the person in the video has a phobia of atheism, astrology, etc.; basically anything anti-Christian.

I wonder how far this sentiments far into the branches of Christianity. Perhaps not to the extreme of this lady, but I feel it fuels some arguments for religion. One that comes to mind is the reductio ad absurdum of 'if we take religion out of the public sphere, we will result into the like of atheistic regimes: Nazism, Stalin-ism, and Maoism.' Of course, one need not look farther than the Scandinavians and the secular US to show that this conclusion is false, but then why does it get mentioned so often? You have nothing to fear, your fear is irrational.

The same could be said for Islam. Their fear is showcased on display here.