That's because it was red.
Combining /mlp/ with /pol/ made for a red pony board. Of course a horse porn board is going to have horse porn.>>123700961
Do you really think the pony fanbase is still large enough to create the destruction you're talking about, let alone sustain it? On a board where even non-offending furry threads, Homestuck threads, etc. get deleted for unwritten rules, you really think the mods wouldn't be able to deal with the anemic ghost of the G4 fandom?