Your refs to Van Gogh pretty much sum up the tenor of the wetcanvas site. A
couple of things:
Van Gogh had no tolerance for mediocre artists--he was vitriolic in
condemning not only such artists but the people who purchased their work.
In fact he was made to quit his job at Goupil's gallery for arguing that
customers should only buy art he considered good and insisted they not
purchase things he considered inferior.
Cutting edge art today found on internet sites such as www.rhizome.org
never achieve universal recognition until a great deal of time has passed,
something new comes along, and people begin to look to the comfort of the
past. Even Duchamp's Urinal, scandalous in its time, seems "cute" today.
Likewise it took people time to understand Van Gogh's art particularly
since it was (and still is) unique. Since he was a loner whose illness often
laid him up for weeks at a time, and his lack of tolerance for anything less
than excellence in anything one tried, he was never a member of a group--at
best, he could only communicate one on one.
Since you seem interested in the artist I suggest you read the 3-vol set of
his letters to his brother Theo and others, containing quite a few of his
sketches as well; as interesting, if not moreso than his writing, since it's
possible to follow his artistic progress from godawful to grand.