I have never seen people get so upset about anything more than conceding putts.
I did some research and it appears that this has been a hot topic since the '50's.
I am posting the basic rules of conceding below:
The whole article can be read at
https://www.thoughtco.com/conceded-putt-1564034
QUOTE:
A "conceded putt" is a putt that your opponent in a match gives you,...
Of course, conceded putts are not required; if you want to make your opponent hole out on every green, make every putt, just don't offer any concessions.
Or you can concede a couple putts early in the match that are right on the cusp of being sure things, only to make an opponent putt from that length later in the match, when the pressure is higher.
Concessions Are Given, Never Requested
Note that conceded putts are not something you should request; concessions are solely at the discretion of the opponent. It's entirely up to you whether your match play opponent gets to pick up his ball without stroking it into the hole; it's entirely up to your opponent whether or not to concede your putt.
No asking for a concession!
END QUOTE
If someone concedes a putt be gracious,.. don't expect it. If you are out of the hole then concede the hole.