that emails and text messages carrying vile content were exchanged regularly between the Scot and Iain Moody, the former head of recruitment at Cardiff.
Only Greg Dyke, the FA chairman, can know for certain whether he was genuinely disappointed or relieved when his organisation finalised its position regarding the accusations of misogyny levelled at Richard Scudamore, the Premier League's chief executive, earlier this year.
An easy interpretation of the official statement attributed to Dyke, however, would be that the FA had cleverly 'finessed' their way out of a potentially awkward situation, given the delicate balance of power between the two bodies that run English football.
"In terms of wider FA disciplinary action, it was advised that the FA does not, as a matter of policy, consider private communications sent with a legitimate expectation of privacy to amount to professional misconduct. The FA has applied this policy on an ongoing basis and in relation to numerous other cases," read the statement.
Accompanying words of disapproval regarding the nature of Scudamore's messages carried little weight. The outcome was that the FA had decided that what went on in an email exchange was nothing to do with them.
So to Mackay and all that surrounds the collapse of what had seemed, until Wednesday evening, the deal which would reunite him with his old chum Moody at Crystal Palace. The pair could be forgiven for wishing they had never met at all should it be proved that the texts and emails came from their phones and email addresses.
Certainly, the apologies they issued to Vincent Tan when they dropped legal cases against him a few months ago must now be seen in a rather different light. So too the lack of curiosity within the football community regarding what lay behind those apologies, even when the Cardiff owner was apparently calling for people to ask why they felt the need to apologise.
Yet, regardless of who wrote these messages, what was exposed once again was that a sub-culture still exists in society wherein homophobic, misogynist and racist behaviour is a part of everyday life.
This is not about the business of high-profile people participating in football being 'role models'. Not even when he was at Celtic is it likely that any youngster watching Mackay was thinking: "I want to be just like him". This is about the sort of society we want to live in.
It seemed that Mackay and Moodie had played their hand perfectly, up until Wednesday evening. Mackay, in particular, had made great play of maintaining a dignified silence - here was a big, decent lump of Scottish straightforwardness who had been hard done to by Tan, a man already consigned to villainous baddie-hood by his club's most fervent supporters.
Once more we were invited to think that these foreign owners just do not understand our grand football traditions. In that context, what is almost as disturbing as the allegations are some of the responses to the story which have been carried on the website of the newspaper that broke the story.
Perhaps the worst of those comments read: "Doesn't take much to 'outrage' sensitive people nowadays does it?"
Having absorbed the original messages, which carry utterly revolting homophobic, racist and sexist slurs, the counter question can only be: just what does it take to outrage some people in this 21st century?
It has, of course, always been the case that those who rail most vocally against political correctness believe themselves to benefit from things remaining as they are, or who believe that they may gain favour by supporting the beneficiaries of the status quo.
However, episodes of this kind expose the ongoing need for closer scrutiny of society, because what some would like to dismiss as laddish banter actually serves as a form of code for some of the most unsavoury elements in our society.
With questions having also been raised over footballing impropriety, the FA can probably get away with focusing on that. However, for those who believe that sport in general is a genuinely vital component of our society, we have to ask ourselves how we would feel if the bodies that oversee of our doctors, teachers, law enforcement officers or, God forbid, journalists were to say that it does not matter what views their practitioners hold as long as they do so in private?
The exposure of hateful attitudes is critical to societal improvement and those who govern English football should consequently take heed. They must revise their stance on whether they should act if and when those engaged in their sport are revealed to be the sort who might make important decisions for the wrong reasons.