The folks over at One-Handed Writers have assembled a set of resources which neatly outline the curious double-standards of pulling down erotica from self-published authors while continuing to sell traditionally-published erotica, torture porn, combat knives and misogynistic books on how to mind-control women (yes, actual mind-control with the intent of receiving actual sex with dubious consent, not fantasy erotica about mind-control).
Take a couple of minutes to look it over. You may well be surprised.