In Italy tips are never required as are a part of what you pay for. You leave a tip for outstanding service if you want, but it’s neither mandated nor customary.

No one's saying they're required. When you say it's not customary, how do you reconcile that with it being printed as part of the bill?

If it is printed on the bill it is not a tip. You must be talking about "coperto", i.e. servics costs. This money does goes to the waiter.