Okay, so I think your question is valid although your feelings come through loud and clear and that is not always the most effective way to start a conversation.
Asking if the Club where you will be teaching would consider leading by example and making a cash donation to the event is a great idea. One word of caution, you will get farther if you pitch it to them on how it will benefit them from a marketing standpoint vs. complaining about how this event is structured.
I can't speak for Spinning Nation in terms of donation. My guess is that if it is like most fundraisers by the time the organizers pay for all the printed materials, t-shirts, jerseys, shorts, bags, etc. that they have to use as incentives to get people to participate in the event they are normally making a considerable donation. I am sure the budget for the hosting the event is quite large. No one would want money the participants raise to go for paying for these freebies to entice participants.
I wonder if one solution, since you were willing to commit your time during the event, would be to just make a donation to the charity of your choice in the amount equal to what you would be paid during the event?
As my Grandmother taught me to ask myself, "Will this matter in a year?" I find that choosing to view the world in this way helps me live a happy life - whether it is someone who cut me off in traffic or my making a mess in the bathroom.
In Peace.
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