The Culture intervenes in and steers those other societies and species even when unprovoked. Essentially a neoconservative utopia as envisioned by a young Irving Kristol. Yes, it would be a heaven for all who are pleased to take on its espirit de corps and live in it, casual and decadently low-pressure such might be, but that doesn't necessarily mean it is a healthy influence in the long run on a universe that it is arrogantly homogenizing. There is such a thing as unintended consequences, and The Culture is not yet one of the more advanced, wiser "Sublimed" civilizations.