I can only speak for myself. It is not belief of which I am intolerant. It is "belief in action" ie: legislating your faith in ways that effect me -- whether I want to be effected or not. That is the height of arrogance, if you ask me. If the faithful could simply worship in peace and leave the rest of us alone, you'd get no quarrel from me. But more often than not, that is not the case.