How can I find out

If the dumb thoughts I have are because of my mental disease or because I'm a dumb person?
I know I'm in the schizophrenia spectrum. I've had hallucinations and I understand I have a tendency not to raciocinate well because of the fact that I'm in the spectrum. But not every time one has a dumb thought is because he has mental disease or because his brain failed. I don't know if was on the internet looking for ways ro kill someone because I was in a psychotic outbreak or because I'm such a bad person that I considered killing my father. I don't know if the fact that I was in doubt if men are inferior to women is because I have some kind of mental disease or because I'm really dumb. How is someone going to be interested in me, if there is no way to find out if I commited these mistakes because I have a bad personality? I don't understand how someone can be interested in me. If people could be sure that all my mistakes are made because of a mental disease, then I could not be considered guilty. But we cannot say that I'm not guilty or not dumb.
I don't wanna date someone who thinks thinking of killing it's acceptable or that we can forgive this. This cannot be forgiven.

I guess I'll just accept I have some really dumb thoughts sometimes and move on with my life.

My diagnosis is schizophrenia and I'm taking meds. But I'm not sure about this diagnosis.
I was thinking he wanted to violate me. So I wanted to kill him as a way of protecting myself. I went on the internet and looked for ways of killing someone *mod edit*, and I remember I was imagining myself killing him this way. I also went to another site and I think I remember myself thinking "I'm going to plan his murder". But I can't even make my bed, I would never be able to plan someone's murder, you know? It takes a lot of effort. And now I don't want to kill him anymore. I was very angry and irritated that day and I think the reason I act like this sometimes is because I believe I'm a bad person.
And the reason I thought men were inferior to women is because for years I didn't have relationships with people. I had a supposed friend who supposably liked me (even though she did something that made me feel upset and now she seems not to like me) when I was 5-8 years old. So if I never had a good relationship with anyone, how am I going to learn about how relationships work, if people are supposed to treat each other equally? Because what I most saw in my life was people treating others differently (including me).

I have felt this way only when completely psychotic. I highly recommend you see your doctor about this as to me, it only went away when I got meds at a psych ward. These to me, are not thoughts that you should have on a daily basis. And I am not judging you, I've had thoughts such as these, just somewhat differently. Let us know what your doctor tells you.