It should be noted that Apple threatened to remove the Tapas app from the store, on the grounds that several of the comics were not what Apple considered suitable content. Tapas had to bend over backwards to avoid the ban, and thankfully they decided to do it in a way that didn't replicate the Tumblr-pocalypse.
Apple are to blame for this, they'd rather throw their weight around and force people to infantalise their content rather than, say, have a more nuanced app store experience where some apps are targeted at adults rather than kids. Honestly Tapas' options were basically a) do nothing and lose the app, b) Ban all adult content from Tapas, or c) try to find some kind of reasonable middle ground. They chose c.