I've had some pretty nasty intrusive thoughts. I'd like to believe it's more than just social conditioning that kept them under wraps. But maybe.

Not all thoughts are consciously summoned, wanted, or pleasant. The term intrusive thoughts is a good way to describe those thoughts we find unpleasant. Yes, they are natural and normal, and often how we grapple with and process experiences, but that doesn't make them unobtrusive.

Additionally, many people have intrusive recollections of upsetting events from the past. Intrusive thoughts is a good descriptor that helps avoid over using terms like flashbacks or PTSD.

Clarifying such things as intrusive helps destigmatize these thoughts for people who have them and feel the weight of social expectations, like new parents as in the comic. Feeling guilty about having these thoughts isn't healthy, and properly describing them as unwanted helps people process them. I don't see what is particularly objectionable or hard to understand about the term and why being more specific in the description of one thoughts is off-putting to you.

I think a good term for what you defined in your edit might be "intrusive thoughts"

They are intrusive thoughts, because that's the phrase that was coined to describe these types of thoughts. Sometimes we come up with specific phrases in order to describe more specific concepts.

There absolutely are intrusive thoughts. Two examples:

Once in a long while, I'll be talking to a black person and I'll think of the N-word. It will just pop into my head for a split second and I'll think "oh my god, no!" and it will be gone. I've never said that word out loud, I've never thought of anyone black that way, and I certainly don't want to think of anyone that way. It's not a thought I meant to have or even a thought that would ever represent how I felt. It isn't even a thought that is pointed with malice at the person I was talking to. It's literally just "N-word" and it's gone. It's purely unconscious and intrusive racism that I think is just part of being white.

Every so often, I'll be talking to a couple I know and imagine them fucking. Just for a split second again. I don't want to imagine them fucking. It's not titillating to me. I don't get a rise out of it. I don't fantasize about it later. But just for a moment, I imagine what it would be like if my perceptive versions of them fucked. We won't even be talking about anything remotely sexual. But sex is part of the human condition and sometimes we have unconscious, intrusive thoughts about sex.

I don't think either of these will lead me to murder. In fact, in general, I don't have violent thoughts, not even intrusive ones. But it could lead me to other atrocious behavior if I dwell on those thoughts and if I let them become more than momentarily intrusive. It's not being afraid of thinking them, it's not wanting to think of them and doing my best to will any such thoughts that stray out of my head as quickly as I can. Because those thoughts are not thoughts I want to have about people. I don't care if I don't act on them either. I don't want to think that about any black people I ever encounter in my life. I don't want to think that about any couples who I know. But sometimes those thoughts just pop into my head and I can't help it. But I can help moving past them as fast as I possibly can so they don't end up accumulating and turning me into a person I don't want to be.

Here, have some of mine!