The community is smaller, the barrier to finding the place are higher. There are several factors that ensure better Signal to Noise ratios in communities. Pr

The community is smaller, the barrier to finding the place are higher. There are several factors that ensure better Signal to Noise ratios in communities. Protective Moats, specific technical subject matter, for example. Essentially it boils down to difficulty to engage, or non trivial effort required to engage. The factors you mentioned have little impact on the behavior of the sub, which is mostly influenced by the people and norms of behavior, over the UI.