Bayer sold the Germany attacker to Liverpool for a fee rising to £125m.
And Borussia Dortmund chief Hans-Joachim Watzke admits he was sorry to see the deal happen as it weakens the Bundesliga.
"It’s a real shame, especially for the DFL, that a player like Florian Wirtz is leaving the Bundesliga,” Watzke told Kicker. "I wouldn’t have had a problem at all if he had gone to FC Bayern.
"That would have been better for the Bundesliga. It doesn’t really matter for the national team. He’ll play at the highest level in Liverpool, too.
"He could have worked better with (Jamal) Musiala in Munich, but two such good footballers can find each other anyway."
In response, Carro snapped: "Honestly, yes. I have a different opinion than Hans-Joachim Watzke.
"I don’t understand how he, as the boss of Borussia Dortmund, could have been happy if Wirtz had gone to Munich.
"That would have made Bayern even stronger. I want an exciting Bundesliga. I’m happy when more clubs – besides us – make life difficult for Bayern, because I believe that benefits the Bundesliga."