SJurgenson
Banned
It commoditizes black men. It reframes black men as little more than sexual props or as a "thing" for white women to giggle about amongst themselves. White men don't receive this treatment, don't have their genitalia reduced to a punchline (Asian men of course suffer from this as well) or as some sort of exotic item. They're men, they have penises. Any race-associated embellishments on top of that are damaging.
You're talking about the direct joke that black men have large penises. Sure, that's a hurtful stereotype we should work to fight against.
But making a playful reference to the common 'BBC' phrase? Now that is problematic and offensive? At how many levels of removal does it end? Is it wrong to mention the Bigger Blacker Box? Someone might get offended if they work backwards from the product name and realize there is a stereotype about penises in there somewhere.