The, "Bad apple" in this case metaphorically represents a Brony in a community of unfitting forum members.
This is the fallacy, Appeal to Tradition
1. Blocklanders are old and traditional here
2. A brony arrives
3. Therefore, being a brony is inferior to being a blocklander.
1. Blocklanders minding their own buisness.
2. A brony arrives posting reaction pictures everywhere, saying stupid pony crap, posting loveual pony pictures.
3. Blocklanders feel pissed off at this friendry and want something done about it.