To give you a more serious resonse. You can blame blame Pioli for refusing to field a certain type of players, thus missing important characteristics that would help us prevent 22 goals conceded in 24 games. I agree, nothing to debate here.
But in the Bologna game, there were too many individual errors who, in my opinion, have nothing to do with the lack of certain characteristics. Beginning with woefully missing two pens in one game. In the instance of the first goal you specifically mentioned, I answered something along you don't need to be a CDM to track your marker. I mean even if we had a CDM, you'd still have defensive duties as a CM. On top of that, Maignan let a ball slip through a goali who's reportedly asking 7-8M should safe, no matter if we lack a CDM or not. Imagine Donnarumma flopping like this. To be clear: I'm not throwing stones at Maignan. I still think he's a top 3 GK in the world. But that was a flop, and it's one that has nothing to do with Piolis decisions.
Terracciano had a promising cameo with Atalanta and everyone was blaming Pioli since weeks for not fielding him more often to close out games instead of relying on Calabria. And now? Suddenly Pioli was too naive to give him gametime because he's not experience (despite playing 1,5 seasons already with Hellas and impressing a lot of scouts, mind you). Heck, and that after there's even been that consistent narrative for months that Pioli doesn't give enough chances to young players, but now that he does, it's wrong too. I don't think it was a wrong decision to bring Terracciano. It didn't pay out, but that's not a bad coaching decision IMO, it's just a young player fucking up his league debut (with us!). That happens. But you see where I'm getting at? Every possible error on the field committed by a player gets always boiled down to Pioli. I don't think that's fair. Not this time.