If someone is sensitive enough to be triggered by a napkin and start squawking about it their opinion is invalid IMHO. That's just someone looking for something to complain about online and hoping they receive some kind of positive affirmation. They aren't offended, no reasonable person would be, they just want attention of any kind to tell them they're brave and special. I actually feel bad for these people because they were raised without any training regarding dealing with the real world, it must be a harsh introduction when they enter the workforce regardless of industry. Fair is not a common word in business, not everyone gets a trophy, only some do.
So yes, I am totally on board with this being a mountain made of something smaller than a mole hill, but since it actually is a thing I must say that I like Delta's response. They totally owned it. "We missed the mark. Sorry dudes and dudettes." That is very responsible, and because they didn't make a big fuss and try to blame Coca-Cola or some airport napkin vendor, it's all over with and everybody can move on. There are a lot of "adults" who could learn a lot from that.