I can't demonstrate they are "ideologically equal" I never said that.
So on what basis does islam have "company"? Simply because you believe adherents of Christianity
may have caused as much destruction as adherents of islam? So in reality you're making a comparison to two sets of adherents, not the actual religion.
To make a sweeping statement over atrocities caused by adherents
X you need to take into consideration much more complex social / economical variables, like for example Europe's control of World affairs (due to economic power) during the Spanish inquisitions etc.
Of course all Abrahamic religions are open to extremism, but that doesn't make the underlying
religion equal.