I don't know if ihollaback is supposed to be a nonprofit but 50% is an awful ratio if so. The is no specific percentage set for a non-profit but industry standard is 10-30% going to admin.
Girl Scouts of America is a non-profit and gives almost 90% back into their programs. FeedingAmerica.com is technically a charity and they give 98% back into their programs.
I get hollaback is not on this scale but still. A lot of people in Non-profits aren't doing it for the money.
Also you might want to check this article out
http://m.huffpost.com/us/entry/6094722
it says what those women make is below the poverty line and those shirts cost $14 to make.
Also, the Fawcett Society (who gets the profit from the shirts) is a UK company focused on bettering women's rights in the UK. Not Mauritius.