I don't think it's the most blatant foul ever, and Donnarumma needs to be stronger there, but you see keepers protected in this context so often, except when it's us.
Personally, the thing that pisses me off is that you're allowed to have a player whose only job is to barge into the keeper or grab his arm, or whatever, and it's considered fair game, when it would be a foul anywhere else on the pitch (as Foden found out). If you jump into someone who's going for a header, even just a nudge, and don't challenge for the ball, it's a foul. But do the same thing to a keeper at a corner, and it's entirely up to the discretion of the ref. When people started similar things to the wall at free kicks, they came up with a rule to stop it. There are so many blatant fouls that happen from corners and free kicks these days that don't get called because they happen early enough to prevent a player from getting to the ball. The other new one is pushing a wide player backwards to make your central players onside. How is that not blatantly a foul? It's not American fucking football.