Hi laughing dog,
IMO, a thought without any accompanying action is neither moral or immoral. Questions of right or wrong only come into play when you interact with the world around you.
If someone cuts you off in traffic and speeds away, an angry fantasy of road-raging the other driver might well pop into your head for an instant. However, if you let the moment pass & stick to safe driving, you did the right thing. Anger is a normal emotion, and we shouldn't be guilt-tripping ourselves every time we have a fleeting "bad thought", if the thought was never translated into action.
Lets say instead you are always short of money, and you start thinking up elaborate plans to rob a bank. If you actually did it, your action would be wrong and immoral. If you started casing the place, bought a gun, researched successful bank robberies on-line, bragged to your wife, etc., I'd say you were also taking actions that would be immoral -- even if your wife turns you over to the cops before you could carry out the robbery. However, if all this planning just stayed between your ears for decades on-end, and you died, then your thoughts about robbing the bank were neither moral or immoral. They were just a waste of mental energy.
Finally, obsessive thoughts/fantasies of a violent or negative nature are signs of a mental health issue, not immorality. Whoever has them needs a medical intervention, before we need to call the cops when they try and act on them.