I'm becoming more and more convinced that organized religion will continue to adapt to modern ideas, as it has in the past few centuries. It's essentially a problem that will take care of itself over time.
My next comment has to do with the following passage of yours:
"[I]t seems to me that openly stating the political agenda of church taxation precludes it being a true political position. "
How? I find this to be a non sequitur. Also, define a "true political position."
Sometimes, politics is like war. The Church of Satan has openly stated that it wishes to destroy Christianity by supporting church taxation. Thus, any political drive pursuing church taxation will be more likely to fail, simply due to the fact that it's associated with the CoS, which is perceived very negatively. I think it could be a feint designed to instill a false sense of security in modern religions. If you know your enemy's tactics, you need not fear them. A true political position, or tactic, is one that your enemies do not know.