Is it always more democratic to involve everyone? I want to argue ‘no’. Rather, I think that where a power imbalance in one arena already exists, the most democratic thing to do in another arena is to weight things so as to give more power to those who are at the bottom of the imbalance.
For example, I would argue that a political system that gave formal political power only to the propertyless is more democratic than one which gives equal formal power to the propertyless and the propertied (though the latter is at least more democratic than the historically more common form, which gives power only to the propertied). That is, the dictatorship of the proletariat is more democratic than universal suffrage.
(Well, it would be anyway, because it is a system of direct, not ‘representative’ democracy, but even independently of that…)
To argue this I want to poke into the notion of ‘democracy’. What does it mean? It means ‘rule by the people’. But who are ‘the people’? How is this category drawn? Surely, it is drawn by looking at who is being ruled – for example, ‘the people’ for the election of the UK government doesn’t include people living in New Zealand, because they are not subject to the UK government (though it should probably include people living in, say, Afghanistan…)