I don't know where I stand on this one actually.
I've been out for lunch. It was busy and there was quite a hubbub of background noise/chat, certainly not silent.
There was one table of two couples with young children and (presumably) grandparents. One child, I'd say around a year old was very noisy. High pitched screeching. She wasn't being naughty, she wasn't crying, she was happy/excited. I realise it's practically impossible to stop a child that age making a noise, but would you expect one of the adults to have taken her out of the room for a while?
Or, she's only a baby, it's hard, let them all enjoy their meal.
FWIW, none of them seemed troubled by the noise, if anything they were enjoying/encouraging it and maybe that's the right thing to do with a happy baby? It was ear piercing though and continued for quite a while.