networkn:
I'd actually look at this slightly different. I think it's valid to apologise, not for the behaviour, but because someone was offended. It's possible to say to someone "I'm sorry you were offended by this", which isnt to say "I'm sorry we made a mistake and you were offended".
Also, sometimes it's easier to apologise, than to deal with the consequences for the apology. Arguing with the customer is rarely a good look.
I recently ate at a fine dining restaurant, which specialises in shared food (think tapas but not quite). 3 Dishes turned up, and had serving utensils for us to move food from the central plate to our own plates. My friend and I (who are not a couple) were happy to share food.
4th Plate turned up, its a large single carrot, and there are no utensils, so I ask my waiter for a serving device. His response was that one wasn't required. I asked again saying I felt it was. He said it was a dish intended to be shared and utensils wouldn't assist with that. I again asked politely for serving utensils. He then got exasperated with us and reached over and picked up my friends cutlery and went to cut the dish in half. We stopped him to which he got upset and got a spoon out and handed it to us. Thankfully another waiter came along with a proper serving utensil (who cuts carrots with a spoon!?).
Bottom line was he was in the wrong for 3 reasons. 1) For assuming we were happy to share food *and* cutlery, which I would expect only those in a pretty intimate relationship may be prepared to do. 2) For touching my friends cutlery which I've never experienced before ever. 3) For failing to take into account that even if I *was* being utterly unreasonable, it was at worst, 2 extra items to wash. There is a 4th one, but in my old age I can't recall what it was to be.
It was an excellent night out with amazing food, but I'll remember that experience for a long time.
In your example it sounds as if your waiter was a bit of a d*ck, so a bit different.
It's difficult to apologize without the implication that you did something wrong. Saying something along the lines of "We're sorry you were offended..." pretty much implies that their offence was warranted.
I think people should apologize if they were offensive (or if a reasonable person would take offense, even if no offense was intended). But in instances of people being offended by what any reasonable person would consider to be inoffensive, it just sets a bad precedent to apologize. It gives people justification to be offended by anything.