LOL...
OP, pretty much everyone who has commented on this thread has indicated that your wife was in the wrong. This is not an opinion, it’s fact.
As has been mentioned again and again, KE (and OZ and many, many others) ALWAYS require passengers to put their seats up from the recline position during meals. Just because you’ve never experienced this before in your self-acknowledged limited flying, doesn’t mean that you’re entitled to insist on what you’re used to. To do so is as ridiculous as someone from the US who has never been overseas insisting they need to drive on the right side of the road in Australia because that’s what they’ve always done...