Why? How does it harm you? Have you ever attended a wedding where children weren't allowed? Do you disagree with that practice?

If you think it's absurd, don't go to that restaurant. Go to any of the other hundreds or thousands of restaurants within driving distance.

This article even acknowledges that kids are never harmless to the enjoyment of other diners.

Some people (and I'm not even including myself here) want to eat around only quiet adults, and it's their right to seek that out and it's a restaurant's right to provide it. It's reasonable for a restaurant to want to occupy a niche.