Havertz is a different type of player, but it is simply that Wirtz replaced Havertz for Leverkusen. So a lot of those comments are more or less "we don't miss Havertz, Wirtz is better anyways"
I was about to write that Havertz shone at the times when Leverkusen were a fairly highly functional possession side under Bosz and went more or less missing when they weren't. Whereas the Seoane version of Leverkusen struggles in possession, but then I checked the stats and saw that Wirtz has only scored a goal against Leipzig and two assists against mighty Fürth in the eight games since the Bayern incident. He's clearly an exceptional talent, but I think at the moment too much of his public perception rests on that crazy 7 game run at the beginning of the season. People were just as enthusiastic about Havertz for a while and it took some time to realize that he wasn't as consistent or dominant as some early runs of form made everyone hope.