It's only dangerous when you work under the assumption that the primary role of police is getting into altercations with people or doing things that require the potential for the immediate deployment of violence. The vast majority of police work doesn't require that.
Some small proportion of police should be armed so they can be called in for the exceptional case, but that's not necessary for most cops. The potential cost and messiness of any kind of use of physical force (armed or not) is usually far higher than the cost of what it's intended to remedy.