most of hirtory men were focused on specific ages for marrying/having sex with a woman If you really research the topic and look at cultures all across the world....
it has been this way for longer than than the modern world has existed....
this didn't "come" from anything new...
it has always been there, the internet has just made it more recorded and visible.
Yeah, I'm not arguing against that. But we are in a developing society, morality, although not dictated by time, takes time to reach societies as they develop their understanding of it. An imposition of will doesn't change over time, it's always an imposition of will. So now we are at a point where we have developed laws that recognize people under the age of 18 as underaged and we offer protections for them, thus, what should follow is a recognition of those participating in a society with such laws that minors are to be protected, and this is typically understood as being the result of an underdeveloped mind, although not rooted in some form of objectivity, but what people feel are the makings of an underdeveloped mind.
So with that, individuals in developed societies shouldn't be seeking sexual activity with minors, but we have avenues, entertainment, that make it such that the lines are rather blurred as opposed to people like that being recognized as the predators that they are, especially now that we can trace some form of objectivity with regards to our understanding of "adulthood".
So yeah, things like biology and history can play into motivating men to seek relationships with underaged women but these are falcious reasons, an appeal to nature fallacy, an appeal to tradition fallacy. I would ask you, if biology the reason for men seeking these girls, why isn't this shared across all men? I can't entertain the history aspect as it's a wash given morality and time, we don't appeal to history as a means of justifying current activity since it's fallacious to do so.
I think with a clear line drawn, on adulthood, we see the removal of the teenaged girl with the older guy in TV/film, the "barely legal" porn, etc. gone, because society would recognize adulthood as being ~25 or even older, thus, the idea of seeking an 18 year old as taboo would follow and it would shunned by the public, which should see to a reducing of the proclivity of men to seek these things out, especially if we then update protections to meet this criteria.
Simply put, I see these issues with age and sexual activity as being primarily the result of the lines being blurred on the topic as opposed to historical reasons and biology. I mean, look at slavery, some still practice it to this day, but in developed societies, what is the reason from its outlawing? Surely, biologically, men would want to dominate those that are weaker, we see it in nature, historically, men have dominated weaker populations. Instead, we have clear moral reasoning on the topic, at least in developed societies, and thus, a reduction due to legality, but even if removed from it and placed in a vacuum, I would expect modern populations to come to the consensus that slavery would be wrong, and they would likely write that into law when establishing a new society.
This is just my opinion on it, as quick and to the point as I can put, like I said, it's much more nuanced than this, and there can really be no definite answers given the complexity of human beings in general. But I do see morality as a check, I steer towards updating our understanding of that, as opposed to chalking it up to fallacious reasons, although, I will easily grant biology playing a part, I just wouldn't appeal to as a means of justifying it, understanding it, I would be in agreement with, just not justifying, which I don't think you are doing.
that your God Allah, smacks the sh!t outta you for typing all this sh!t I ain't reading. 
