We must keep in mind that Tarot cards were originally made for trick taking card games long before they were used in esoteric or occult practices. If there's any real religion in the original Tarot, it was in the use of themes of the popular Catholicism of 15th century Italy to illustrate the trump suit. The actual underlying Tarot card game of which there has been numerous regional variants across continental Europe is suitable for anyone regardless of creed.
I also wish to mention the fact that all these Rider Waite Smith knock-offs we see in our popular media are not the only kinds of Tarot deck. In the 18th century, German card makers began making a type of Tarot using the same French suit signs as our Poker deck. The trump illustrations varied considerably from the earlier Latin suited design. French suited Tarot cards may depict animal or genre scenes and they are currently most often used in countries such as Austria and France. It would be good if more Americans were familiar with these cards. It would be especially good if more American Tarot writers were familiar with French suited Tarot cards as these writers seem to be only aware of American made cards and this parochial outlook cripples their ability to write on the topic from a more global perspective.