I think that is what you think is being said.
Irrespective of which ie either the father or the mother was at fault that their relationship broke down, it is just as likely that the son resented being made to move from an area where he had friends, etc. Felt safe and so on.
His behaviour deteriorated following the separation, and his removal from a situation he was familiar with.
And all too often when a son is left (if not abandoned) by his father to just have his mother in his life, more often than not the mother is blamed for not staying with the father.
It maybe that he was not only more isolated, lost friends, but could aslo be living with less financial resources. Or no longer has the familiar and preferred urban area to somewhere more rural.
So whether the father was a complete shit, and or violent or had found another partner, not just sons, but perhaps more so, resent being made to pay the price and all too often becomes negative towards women.
It is just as likely that it was this lived experience rather than the virtual world that caused his attitudes. Although of course Discord or any number of incel spaces would have been happy to confirm his notion that he was the victim in being made to live with his mother.
Obviously I cant claim this is the case here, but certainly there are any number of family breakdowns where the children are assumed to then be the responsibility of the mother. And too often the absent father excused and the mother blamed for the lack of involvement of the father.