Go with the members you’ve got, the rest will join later.
When you start your community building efforts, many people wont join. Not right away. It doesn’t matter how persuasive you are, many people just don’t want to risk their time on something ‘new’.
Others will act snooty towards it. They’ll bash it and criticise it until they can’t afford to ignore it anymore (See: Twitter/Facebook).
You can waste a lot of time trying to persuade these people to join. Ignore them for now (that includes their insults). Focus on the members that you’ve got.
Spend your time on those that believe in your community. Increase the value of your community from the inside. The rest will join later, if you let them.