When MongoDB is installed as a service on Windows, users will have an expectation that the database will keep itself available across system restarts. It does this fine when the system is shut down in an orderly way, but on a power failure or bluescreen or system crash, mongod.exe can't start up without some handholding because of the leftover mongod.lock file. If we just auto-restart, we fail immediately because of the leftover file. If we don't auto-restart, then users will wonder why we're not running and have to go do something to fix it.
It would be a lot better if we had a scheme for climbing out of this ditch and could make the code just recover automatically (when possible) and issue notifications to administrators to please come and intervene when that is required.