You're pretty much correc, Mitch. The DNC registry is for telemarketers, meaning sales. Charities, debt collectors, political speech, and surveyors are all exempt as they are not included in the FTC definition of "telemarketing". This was made known to you when you registered your numbers.

However, much of the charity phone bank work is farmed out to so-called "commercial fundraisers" such as Associated Community Services, Dial America, and InfoCision. These for-profit firms don't quite get the same blanket exemption. Here is the holy writ of FTC: "... if a third-party telemarketer is calling on behalf of a charity, a consumer may ask not to receive any more calls from, or on behalf of, that specific charity. If a third-party telemarketer calls again on behalf of that charity, the telemarketer may be subject to a fine of up to $16,000."
 Dec 03rd, 2010
I called the number to see who it was, and the woman said she was calling on behalf of the National Children's Center to schedule pickups of contributions in my neighborhood. I believe charities are exempt from the Do Not Call Registry, but based on the comment below from 4/24/09, it may be that the number belongs to someone who calls on behalf of both charities and businesses, earning commissions.
 Dec 03rd, 2010
Recorded message received 8:17 PM on 4/24/09 stating something like you have a vehicle whose warranty is dangerous near it's expiration date. If you are interested in obtaining insurance dial 1. I dialed one and a live male voicecame on the line asking for the make, model and yr. of my vehicle. I said, you called me, you should know. He responded, no you dialed 1, calling me, you need to give me information. When I tried to proceed, he would not listen and tried to sppech over me, calling me Karen. I had not provided my name. I stated, I am on the do not call list and I have you phone # and am going to report you. He hung up.
Name on caller I'd was Kenneth Little at 301-460-7557
Karen White
 Apr 25th, 2009