Anywhere that sells alcohol has to be licensed to do so. Protection of children, not just from alcohol, but the effects of others under the influence, is part of that license. Certain conditions such as times children must vacate the premises have to be adhered to or risk losing it all together.
Most policies like the one this restaurant have are dictated by the license. We don't allow children in after 9pm (license condition) so we don't allow children in the restaurant to eat after 7, so people aren't rushed.
People ought to have a right to dine in peace, without being disrupted by other customers. If they are not disturbed, it should be no one’s business if there are children there.
Except the licencing officers and police, and the premises putting their license at risk, and the people allowing it (the waitress and manager in this example) who could get a personal fine.
Age discrimination is illegal. I would like to see a test case on this.
Yes I can see it now.
"And why don't you allow children in your restaurant after 6pm?"
"Our license prohibits it, it would be illegal"
"But that's age discrimination"
"Which law should I break then?"
Of course it could be that it's not a license condition, they just don't want children there after a certain time. But that's their call. Pubs, restaurants etc are free to make their own rules within the law, that works for them.
YABU OP, and if it was your favourite place, that indicates service you are happy with generally, and not rude staff in general, until, of course, you were told something you didn't want to hear. Some people really do think that being told no is rude, regardless of the reason, how it's put across or anything else. The 'I want' demand isn't met and then the staff are accused of being rude because the customer is disgruntled that they can't have their own way, and saying the staff are rude makes them feel justified.
Oh and I don't ever apologise in a situation like this. Sympathise yes, but I wouldn't apologise in this situation. An apology indicates you've done something wrong that you need to apologise for. The staff didn't do anything wrong, therefore they have nothing to apologise for.