Peace keepers are heroes and friends. Children want to grow up to be peace keepers. People like to help the peace keepers do their job. Peace keepers don't have to be busy, their visible presence discourages violence, that's why they wear uniforms. Since they can be friends to all but the violent they form strong bonds with the people in their communities.
People generally join the police because they want to be peace keepers.
Regulation enforcers are generally despised and avoided. Few are proud have regulation enforcers for friends. Children rarely want to grow up to be regulation enforcers. Regulation enforcers have to stay busy to do their job and to reduce their visibility they often avoid wearing uniforms. Since there are far more regulations than people are willing to obey there is always more work to do.