You sound a lot like my wife. A doting grandma.
“watching him enjoy himself” at home where he bothers no one else to bother and the mess is his to take care of when he is done is fine. But when he is in a restaurant with other patrons that are paying for the privilege to be there and being molested by another’s unruly child is not something that they came there for is another matter.
Children need to be able to explore and learn about their world from time to time in a free and unfettered way. But those times need to be at home or at a relative’s home (grandma’s) and when they are done they need to be responsible for the cleanup so that they learn to be responsible for their actions.
He was always well behaved. But I agree parents shouldn’t let their kids run around or make messes like they would at home. I don’t really encounter that in restaurants. Once or twice at a buffet way back, but we seldom go to those because the food just isn’t all that great imo.