The more I look for diversity in religion, the more sameness I detect. As I turn the resolution down and distance myself, one looks pretty much like another to me.
But up close, microscopically, the Jw's and some other cultish groups are more dangerous to the membership. The more insular, the more introverted socially. The damage is real from these groups. So in some respects, certain religions can be different enough to bring serious matters to roost for the membership, that more liberal groups would not. Jonestown, Koresh, Hale Bop come to mind as extremes in this regard.
Jeff