Not sure what is the best strategy - not join NEMBA because you disagree with them, or join them and change from within. Probably change from within. The NRA used to be against modern rifles like the AR15, and many people refused to join them because of that. But what happened was they had to change to what their members wanted, and their members wanted modern rifles. So any board of director member who was against modern rifles was eventually voted out. Perhaps join NEMBA and vote against anyone who is either advocating to ban eMTB, or won't publicly voice support for them.