As slow and cumbersome as public discussion can be, it’s almost always preferable in the long run. Making important decisions in private is like spraying contributor repellant on your project. No serious contributor would stick around for long in an environment where a secret council makes all the big decisions. Furthermore, public discussion has beneficial side effects that will last beyond whatever ephemeral technical question was at issue:

Karl Fogel “Producing Open Source Software”

The important part after this is that you need to “Nip Rudeness in the Bud”. Every contributor deserves respect as a person. Always.