Lemme get this straight.
MC's dad was accused of rape, and being an all around creep, so MC decides to .. Become a rapist and all around creep to get revenge?
Mentality behind that makes sense in a twisted way. MC's life was absolute hell growing up because of a mere accusation some scheming whores did against his father. The father got all the suffering without having done anything (that is how society often is in real life too, some womans mere accusation is enough to ruin a mans life, whether the accusation has any credibility or not), the MC suffered from it as well despite both him and his father being innocent, having a very traumatic and poor upbringing as a result without any fault of his own, getting abandoned by his heartless golddigger of a mother, who I still deem one of the select few characters I wanna see meet a brutal end before this story is over.
If you already got punished for a crime, directly or indirectly, despite having been innocent, then you might as well freely do the crime with a clean conscience from that point onwards if you feel it's appropriate, I know I would, because obviously the justice system completely failed me in that scenario, so I would deem myself above it afterwards.
To be fair, some of the girls outright deserved the treatment. His stepsister for example tried to get rid of him on day one, with the same kind of false sexual accusation that was aimed against his father and ruined his childhood, all over her expecting to get a smaller allowance due to him being there. She tried to ruin his life (he woulde have been kicked out, possibly charged, expelled, worst case went to jail, more likely than even the average man due to his family history) over some pocket change, despite him being family, there was no revenge she did not deserve afterwards. Instead of taking brutal revenge he merely molested her in her sleep a few times until she wanted to fuck him anyway, he pretty much made her happy by tricking her and messing with her brain a bit, and was considerably less brutal than one would expect in that situation, with that background.