I was first introduced to this concept after I saw two men almost crying over football who had remained stony and strong through a bereavement earlier in the year. Football for some (especially working class men it seems, but not exclusively) is a proxy through which emotional bonding and interpersonal involvement with loved ones has happened, a connection to family as well as an outlet for emotional energy. A trivial thing it's ok to cry about in a world full of things that must never bow your head. Just as other things can be from one family or culture to the next.
That is not actually relevant to the case in the OP - you are taking your argument about the importance of football to an extreme length that is not what is being discussed here. I didn't say football was meaningless - I think interests and hobbies are very important ways of connecting and definitely have an important place in people's lives.
However when those interests start to affect the way you interact with others in a non-beneficial way,t hen you need to sort out your priorities and weigh up what is really important.
Having been on the receiving end of someone who put his obsession above his entire family and hurt many people in an irreperable way over it, my empathy lies firmly with the victims of obsessive interests.
So I don't lack empathy - I simply have different priorities and find different things important, people are more important to me than hobbies, despite the value of hobbies. It is a scale of importance, I am not assigning no importance to football.
Just as your experience informs your choice of empathetic stance, so does mine, I find it odd that someone who advocates the importance of celebrating difference, should be so blinkered when someone offers a different viewpoint.
If football is a 'proxy through which emotional bonding and interpersonal involvement with loved ones has happened' then OP's husband has failed spectacularly to use it as an opportunity to bond with his son, because of his childish and cruel behaviour.
It is childish and nasty to throw away a child's birthday present. No pop sociological spiel about the importance of football in the lives of working class men as a means of releasing suppressed emotion can change that fact.