Chewing someone out on the frequency is counter-productive. It may make a controller feel better at the time but it can only exacerbate a conjested frequency and kill any rapport the controller has with pilots on at the time.
Agreed. The only exception is when the pilot is SO far off base that even other pilots start turning on them.
As for the VATSIM example...my problem with VATSIM is there are so many people who participate at different levels. Many of the pilots flying around the network have very little knowledge of IFR procedures or even the basic flying. In the real world controllers expect a certain level of knowledge and awareness on the part of all pilots, especially those flying IFR or in busy terminal areas.
Yes, it's an ongoing problem, but the network is generally worthwhile, and there are enough solid pilots to sustain a good experience.