For about the past three months I've been conducting a small experiment. When I've seen people misbehave on the Debian development mailing list, I've sent a private e-mail to them suggesting they should avoid some specific behavior, in the hope of getting them to stop.
My success has been varied. A few have thanked me, and changed their behavior. A couple have taken offense. Some have ignored me.
I've noticed a correlation between how much effort I put into the letter and how successful it. Broadly speaking, if I send anything earlier than the sixth version, it fails. Getting the message exactly right is not easy, for me, and takes quite some effort and time.
I'm happy about my successes, but on the whole, I fear my experiment is a failure. It's too much effort to do this in the long term, and it's too chancy. Someone else might be able to do it better, but this is not something I can keep on doing.
I think we need some better solution to keep discussions in Debian on track and not have them blow up. We have a systemic problem where contentious issues, such as choice of init system, is quite hard for us to deal with. We're also not very good at dealing with situations where a few individuals are dominating the discussion by being loud, insistent, and unwilling to budge or to give any credence to opposing views. I don't know what to do about that, but we clearly need social and possibly technical tools for this.