Funds are donation or membership dues. There are quite a few restrictions on how they can make their funds and how it's spent.
Also, most 501(c) organizations will take just about any opportunity to increase income. My question is the movie isn't advertised on the website, much less anywhere other than the article.
From the the supporting foundation about 2 years ago:
Revenue
Primary Revenue $20,731,298
Other Revenue $6,916,912
Total Revenue $27,648,210
Expenses
Program Expenses $42,973,082
Administrative Expenses $2,197,270
Fundraising Expenses $1,176,193
Total Functional Expenses $46,346,545
Payments to Affiliates $0
Excess (or Deficit) for the year $-18,698,335
Net Assets $54,646,025