The former Morocco international and Olympique Marseille sporting director was speaking on Canal+ when he discussed Alonso's departure from the Spanish club and the wider imbalance of power between coaches and dressing rooms.
Benatia, who played alongside Alonso at Bayern Munich, believes clubs increasingly find it easier to dismiss a manager than confront a group of players.
"Players have too much power now. It's easier to change a manager than 15 players," he said.
He then pointed to Alonso's experience at the Bernabéu, expressing his disappointment at the way the former Bayer Leverkusen coach was treated.
"When I see an institution like Real Madrid getting rid of Xabi Alonso... I had the chance to play with him. There aren't many teams that have dominated Bayern Munich the way he did with Leverkusen. Incredible!"
Benatia did not hold back when describing Alonso's departure.
"He was kicked out like a piece of s*** from Real," he said.
The former defender believes Alonso attempted to introduce clear principles and standards at Madrid, drawing on his own experience as a player who had won major trophies.
"He tried to put principles in place, saying: 'I've won everything as a player, so this is what we have to do.'"
However, Benatia suggested that the coach's authority was undermined by the dressing room.
"That lasted three months, the dressing room turned against him and then you're gone," he added.
Alonso's departure from Madrid came after a difficult period in charge, despite the reputation he had built during his successful spell at Bayer Leverkusen. He subsequently took charge of Chelsea, providing an immediate return to management in the Premier League.
Benatia's comments reflect his wider concern about the growing influence of players in the modern game. In his view, clubs are too quick to sacrifice coaches when tensions develop, rather than addressing problems within the playing squad.
His criticism of Madrid was particularly pointed because of the respect he retains for Alonso, whom he knew from their time together at Bayern.