Both the club and the city are responsible.
You've not seen any qualified person speak about it? I was there and lived through it, the organisation from the city was shambolic. Anyone who was there would tell you the same thing, bordered on gross negligence.
Juventus should have opened the stadium up to the fans, Like Real done, hell even Inter done it in 2010. Some fans have told me the club didn't want to open the stadium because it would've cost them money, can't confirm or deny that. But there's no doubt they should have opened it up. There would've been no glass, no overcrowding, nobody would've got hurt.
With a club that has Heysel in its history, it's outrageous that Juventus don't do right by their fans. Even people trying to get tickets for the final (a separate issue entirely) was shambolic and amateurish.