The phrase "pure arrogance" refers to a high level of self-importance and superiority, where someone thinks they are better or more superior than others. Full definition
It is just pure arrogance of humans they we, as animals, are so special that we can't possibly die without something happening to our spirit. (religion.blogs.cnn.com)
It nothing but pure arrogance to think he can find his. (justarsenal.com)
For anyone to say god any god exists is pure arrogance as much as for those to say one doesn't. (religion.blogs.cnn.com)