15 Love or 15 nil/nought/zero?

Henny Penny's all hot and bothered, is he?
Quel dommage!

I suppose I have been a bit uncritical of the common explanation, but while you have persuaded me that I should not consider the explanation that I have presented as being definitely correct, you have not come close to convincing me that yours is correct. The one that I presented is commonly accepted and makes sense. You have presented two contradictory putative explanation for which you have given to cites and which doesn't really make sense. You seem to not understand what the phrase "for love or money" means. "I wouldn't do it for love or money" means "I wouldn't do it for anything", not "I'd do it for nothing". I can't imagine anyone saying "My score is love or money". That doesn't make any sense. Similarly, simply because the phrase "play for love" is used to indicate that no money is at stake, that does not somehow mean that "love" is understood to mean "nothing".

Another Guest is addressing Damian.

We are still waiting for the anti-L'Oeufians to explain why, if the tennis score "love" is derived from the phrase "playing for love" and not from the obvious 0 = goose egg = L'oeuf = "love", why did it then become necessary to describe a nought-to-nought score as "love-all" ?

If the anti-L'Oeufians are correct, then the term "love-all" would seem to promote the intolerably nonsensical* inference of a partial inverse : to wit, that in a given tennis match one player (or one team, in the case of doubles) could be merely playing for the love of the game without especial regard to the outcome, whereas by contrast the other is busting a nut striving to win the same match.

The ball is in your court.

The asterisk was for this :

* [I say that in isolation, for I am quite fond of a good piece of nonsense, in the literary tradition or otherwise, from the Irish bull to the Mad Hatter's riddle.]