Warren, it's not particularly church members who rationalize away apparent intellectual inconsistencies. Again, it's human nature, and we all do it, especially when we are strongly committed to an ideological position. Citing authorities external to a sacred text for the meaning and interpretation of the text doesn't necessarily imply that one doesn't view the sacred text as ultimate authority. The SCOTUS approach to the U.S. Constitution is a good example of this. 

As for your other question, I will cringingly veer off topic. When it comes to laws that provide special consideration to religious corporations (such as ERISA exemptions), I do not see how matters of faith should constrain the business decision of the corporation from availing itself of those laws. Should a Christian, tempted to utilize the rules of the tax code to deduct charitable contributions to his church, be deterred from making a business/legal decision by religious considerations? I don't think so.