Donations used to influence legislation not tax deductible. Evangelicals?

I just donated to help air the MoveOn.org Social Security AD. I noticed the following disclaimer:

"Contributions to MoveOn.org are not tax deductible because they will be used to influence legislation"

Now evangelical groups solicit and collect donations on a TRULY MASSIVE scale, and those funds most certainly used to "influence legislation". It may not be called a "PAC", and they may not be reporting to the FEC, but they are most definitely engaged in direct attempts to influence legislation. Further, those contributions ARE tax deductible.

Consider James Dobson (of recent fame for his anti-gay crusade). People make donations to his "Focus on the Family". Focus on the Family uses that money to develop their website. They post pages with anti-gay activism links, and engines to write letters to politicians and the media to ... influence legislation. Yet donations to "Focus on the Family" are tax deductible. And the same considerations apply to Jerry Falwell's Moral Majority, Pat Robertson's Evangelical Empire, and even small local churches that shill for the conservative political agenda.

This is inherently discriminatory behavior, and it puts progressives at a disadvantage. They are taking advantage of accounting sloppiness, counting "their ministry" as all of their activities.

Does anyone else see this as a systemic problem that puts progressives at a disadvantage, and something that should be investigated?

and ridiculous. But good luck changing it. The christians control the entire power structure in this country.