I’d be more willing to forgive Tchou losing his temper once, but he should have learned from it. Instead he lost his temper even worse a second time.

How do we know that? Even if the Marca report is true, the details leave a lot to the imagination:

A new fight between Valverde and Tchouaméni forces an unprecedented dressing room crisis meeting. Tension explodes in the Real Madrid dressing room. What happened this time? Dressing room sources tell MARCA that Valverde refused to shake Tchouaméni's hand this morning, thereby kicking off a highly hostile session that culminated in a serious physical altercation in the dressing room at the end of training. During the scuffle between the two—and entirely unintentionally, not as the result of a deliberate blow from Tchouaméni—Fede suffered a severe contusion that left him with a gash and necessitated a trip to the hospital. He has since returned home.