"Preaching to the choir" usually means doing something you don't really need to do. Those folks in the choir -- they're already on board with your message. They don't need to be told. Focus on the other people, the ones who aren't yet with you!
Well, no. Says Seth Godin at Preaching to the choir: If your work is worth doing, it’s worth preaching to the choir.
The choir is exactly who you should preach to, precisely because they are already on board. They understand your message. They get it. They are predisposed to take action.
All those other people? Some of them are interested. But most of them aren't. You can preach until your larynx is shredded -- most of them aren't listening.
What you should do instead of preaching at them is invite them to join the choir. And then preach to them.
Your cause, your message, is not for everyone. It's for the true believers -- the choir.