Maybe when Blanc congratulate him after Melo scored, Atalanta came back to score a 2nd so I guess Secco told him to hold the congratulation back ... Otherwise I couldn't find a more valid explanation for Blanc not to feel pissed.
I have better explanation. Secco told Blanc before the match that Diego would score, but Blanc insisted that he won't. Then, Blanc fined Secco, as he was stubborn on that matter. After Diego scored, Blanc told Secco I'm sorry and want to handshake, but Secco told him leave me alone and started crying.
Maybe when Blanc congratulate him after Melo scored, Atalanta came back to score a 2nd so I guess Secco told him to hold the congratulation back ... Otherwise I couldn't find a more valid explanation for Blanc not to feel pissed.
Maybe sSecco saw blanc picking his nose earlier or placing his hand in a very disturbing position and when blanc decided to hi5 secco remembered where the hand of the frenchie was. I'm just spectulating