ServiceLevelEvents(SLA) should be the agent that is responsible for running the purge and archive. This agent does a lot of things other than purge/archive. It is not recommended to stop this agent.
The queues must be present in system-queue-servicelevel as it is the queue of SLA agent. I'm not sure if there is any way to block the purge/archive on a particular node other than stopping this agent, which is used by a lot of other functionalities.