Anyone who uses Ostracism to dispense the competition.
When I mispelled "Wikipedia" as "Wikpedia" the Wiktionary system administrator acted like an Ostracist by blocking my access and calling me a vandal and a troll.
Anyone who calls another person a troll.
Joe only called John an ostracist after John labeled him a troll.
Don't join that club unless you want to become an ostracist.
Don would probably make a good bouncer since he likes being an ostracist.