@ depenz
Is it normal to not get a boner from vanilla porn, but only from violent porn, when the girls cry and get "raped"?
No that is not normal. You shouldn't even need porn to give you a boner in the first place. I was just as you describe at one point, I could only get it up to aggressive/abusive hardcore porn compilations at one point. No chance getting it up to the stuff I started out watching, I had escalated into some stuff that gave me a sick feeling in my stomach when I was done.
The anxiety and shock of more "extreme" porn or novel porn can increase dopamine. If you have always only been aroused by violent/rape porn then I would still do a reboot but also seek further professional help.
The reboot does indeed take time, but you need to be patient and proactive by replace porn in your life with healthy and productive things.