Your pitch is toned for the audience.
If your audience shares your commitment to the community-- then the potential positive return for the community can be the primary focus of the pitch. If the audience is being solicited for an investment in which they are expecting a financial return, then omitting the profit potential from your pitch will be a bad idea. If your pitch is for a philanthropic donaition your pitch needs to regflect an understanding of the motivator factors for the donor.
the essential commonality of a social entrepreneur and a traditional entrepreneur is that in both the underlying business has to stand on its own feet. Regardless of whether the social entrepreneurial endeavor is for-profit or not-for-profit -- there still needs to be a solid business model which shows how a need in the market is met and how the costs associated with the need being met are paid for.
As a social entrepreneurial you need to have a mind for business -- and the good for your community.