A word of advice, if you care to hear it, is to see how an organization is funded. Privately funded, especially family money funded, non-profit organizations are typically seriously dysfunctional and abusive (take the Casey Family foundations in Seattle for example, I worked for one, seriously disturbed, sick and sadistic abuse from the president down, 100% turnover in staff, etc.).

The more accountability an organization has (those who are funded by public funds and have to answer to the public) are typically healthier organizations for which to work. Of course there are exceptions.

Having volunteered in every possible way for non-profits (from one off event volunteer, to volunteer coordinator, to staff member, to board member), in my experience (which spanned 20 years), the non-profit world is not much different from the corporate world. I worked in the entertainment industry (music) which is the worst of the corporate world because corporate culture + pretending we're cool because so many people want to work for us = the absolute worst in company culture.

Dysfunction and abuse exist everywhere, it's a matter of really paying attention and not getting into a situation you will immediately wish you hadn't. The non-profits treating you like shit are doing you a favor in that they are telling you exactly what it would be like to work for them.