This isn't absolutely universal, but parents/guardians are often the main source of a child's validation. Children need guidance, and before long they may come to expect it in some form and, hopefully, seek it out. When someone fails to live up to the responsibility of guiding their child, it can feel like a betrayal, and the child may feel that they can't count on the guardian.
My reading of the soccer scene was that Eugene was consistently failing to be an attentive father, and regardless of whether he had a legitimate excuse on this occasion, it had come to be an expected pattern that he wouldn't be involved in his son's life. Sara had a whole speech prepared.
It's not that the soccer game in and of itself is what was important to Roy (although Roy clearly was working hard to carry his team to victory); it's that Eugene didn't care no matter what Roy did if it wasn't wizardry.
This, I admit I have a hard time following. Are you suggesting Eugene consciously chose to be cold to his son, due to his relationship with his own father? Because if any connection can be made, the one I see is that Eugene is a smarmy intellectual whose fighter-phobia exceeds his minimal love of family.
I think Mightymosy's understanding of this fact is implicit in that he made a thread to ask whether or not the "sports trope" is common real stuff.