Diplomacy bug?

Some cities are neutrals and not one of the main factions. 

I think that's the reason.

So how can we start diplomacy screen with neutral cities/factions?

Are two of the four, minor races?

To tlak to one of the minor races click on one of their units (or their city and then one of the units in the city) and then click the action bar and there is a start diplomacy button

I think minor races should have its place in diplomacy screen

I agree if its a matter of wanting to restrict how much we can do with them then limit them by controlling what diplomacy topics can be negotiated with them.

What's the use of diplomacy with those minor factions? They have nothing, do nothing...