Sentence:  To the pantheist or monist [mystical experiences] are experiences of the One, which is identical with himself, and which is probably the same in all religions and even in secular mysticism. In face of this easygoing tolerance or <WSD>indifferentism</WSD> it is perhaps not surprising that monotheists are often intolerant, believing that God has chosen them and by implication not others. 
Meaning of the word marked with <WSD> tags:  The doctrine that all religions are equally valid.