But this happens in any organization, even political ones. I might join the NRA, but disagree with them on say, background checks at gun shows. And here they are using my dues to fight the gun show law that I agree with. I can either quit or attempt to take over the organization.
Same way with the ACLU. They strongly support Citizens United, yet most of its critics are probably in their membership.
But people will still join the NRA or the ACLU because they generally represent their respective interests on MOST things. If you had a rule that said an organization can’t promote an issue unless on a unanimous vote of its membership, then you stifle any effort of people to meaningfully petition or assemble.
In other words, you join the NRA or the ACLU, or buy stock in a corporation with full knowledge that you can be outvoted on things and that the organization may do some things that you don’t like. You join anyways because the things they do that you like outweigh those small things. Otherwise, you can withdraw.
I’m not seeing the problem that calls for a blanket ban on group speech.