Jokes can usually include a message, and often are more effective at delivering that message than a serious monologue with full citations.
Therefore, saying something is meant to be silly or a joke does not do anything to address whether the message behind that joke is a good one or not.
They can keep their guns if they pass mandatory training.
Most cops don’t ever fire a weapon on duty over the course of their entire career, so most of them don’t actually need to be armed all the time.