I haven't ignored it, there just isn't any reason why gamete health would be the only biological constituent of attractiveness.
Well, you said there is 'evidence' that older men are more attractive for 'biological' reasons. In that case, surely the fact that the older a man is, the less likely he is to be able to contribute to a viable pregnancy is highly significant? Especially as you have provided zero evidence of any biological advantages which older men have to counteract this.
For starters, male gamete health peaks at an age at which historically most men would have been least well equipped to provide for their offspring and the mother of their offspring (maximum volatility, minimum accumulation of resources)
But that's not 'biological'. That's sociological. For the vast majority of human history, we were hunter gatherers with no 'resouces' to accumulate, and anything there was was shared within the group. So no reason at all for a woman to seek out a decades older man, but plenty of reasons to seek out a virile young man with healthy sperm.
Only that it isn't unusual for young women to be attracted to much older men, hence the many tropes and cracks about daddy issues etc
I would say it is pretty unusual, and the actual statistical evidence - which again you ignore - bears this out. Again, if middle aged dudes were so 'biologically' desirable, surely they'd be in greater demand?
There's a relevant excerpt from the linked book here, I didn't realise that previous link was a dead end
I'm not going to read the whole thing, but assuming you have, can you point to the part where it provides evidence that older men are biologically superior to young men?