Ordinary Banana

Explain self-loathing to me. I get misery and I get wanting to die but I don’t get self-hatred.

Imagine an inverted narcissism: Your locus of consciousness is not "in you" most of the time, like it is in most, but instead outside, observing. You see that the primary cause of all suffering you see (your own and others) is the actions of your self, and so you blame this self.

Whereas the narcissist takes as axiomatic that he is good (and other, bad), the self-hating does not. The self-hating simply sees that the only common factors across all negative experiences is himself, and then runs with this.

cognitive behavioral therapy sees it as straight narcissistic but your picture makes more sense

CBT generally has no insight into any psychic issue with real depth and/or characterological origins, IMO. Although it is good at modeling the surface-level thoughts / appearances of things.

yeah I found it fun for about five days and then useless/stupid

CBT explicitly does not CLAIM to have insights. It claims to FIX. Does a splint or cast need insight into a broken bone to accomplish its task?