It's not stupid. Plenty of times playing through pain won't do any more damage. Even in this instance, for all we know all the damage was done in the initial incident and playing through pain caused just that. Pain. Enduring pain for the sake of your team is brave, not stupid.
You're dealing in a rare scenario where playing for a lengthy time doesn't worsen the injury. There's no way for you or me to know either ways whether that's the case here. I'm talking about a normal scenario where playing on with an injury does worsen it. Being sidelined for a length time as a result costs the team, it's brave in the very short term but stupid as it costs the team long term. It's why LVG was livid at Rojo too who did the same.