
That argument doesn't really hold water. No matter which country you want to focus on, pedophilia was always largely regarded as disgusting. While some places practiced child marriages, both ppl in that marriage where kids. Others did early engagements, but mostly kept small age gaps with large age gaps being very rare and looked at sideways. Not to mention being mostly noble exclusive and looked down upon by the general populace. While there were places where nobility normalized same sex pedophilia in men, there were places where that too was looked at as horror. Like, when using that argument I'd like it if a person focused on a particular area, so I could talk about it more specifically.
The rsn to make the bastard one half of an incest couple, is so we'd casually overlook the pedo situation of the main couple.