I happen to be a VATSIM controller and yes, it does require training and a process to officially control virtual air traffic. In so many cases, it is not different from real-world ATC, given the limitations of the simulation environment. Yes, I’ve heard stories of impatient controllers but most are here to provide an enjoyable experience for pilots of all experience levels. Using online ATC is a two-way contract - Pilots need at least a basic understanding of ATC procedures and controllers need to know the regulations and procedures, and, a level of patience and understanding to keep everything working efficiently - no different than the real world.