Because religious belief can be used as an excuse (supported by what is claimed are the words, or beliefs, or writings, of something - or someone - or someones - deemed divine) to suppress or deny rights to others, that is, groups in a culture or society that have been traditionally deprived of rights with religious belief used as the justification for doing so.
Having said that, I do think that the title in question is both too broad, and too general, - not all "tolerant" folk would hold such opinions, or views, for example, - and the use of the verb "hate" is, I would respectfully submit, a little too strong, in the circumstances.
"Dislike", or "despise" (on occasion) or "distrust" would seem to me to be somewhat more accurate.