I think it's possible this obsession with violent sexual acts stems from anger, at least in part, towards the life situation in general, society, women, oneself. It could also be that you don't know how to express that anger and distress in other ways.

Whatever the reasons are, in my opinion it would be good to try and somehow stop them from taking over, because while it's alright as long as you don't act on them, there's a very thin line and it can turn you into an actively violent person towards women without you even realizing it or wanting it. Besides, even if it doesn't, just like porn and the messages sent by society, these thoughts can in time shape the way you perceive women and relate to them.

I say this as a woman who is also very very lonely and who watches pretty hardcore stuff sometimes purely because anything depicting something I actually crave and desire to have, makes me cry not get aroused, so I have to watch things that can be fantasies but I wouldn't personally engage in. We can all go to unexpected lengths when it comes to coping with our needs and so on, but it's important not to let those things, if potentially bad, to make lasting changes to the way we see the world.