Respectfully, I disagree. Numerous times in media we see a furious character punch walls until his knuckles bleed, or clench fists until her nails draw blood, or some other similar reaction, to push further with that angry adrenaline. Precedents for self-harm-fueled raging exist.
— J. N. H. (@chaoswolf1982) December 25, 2018
You’re actually agreeing with the rule. Barbarians can deal damage to themselves to keep raging.
— Jeremy Crawford (@JeremyECrawford) December 26, 2018