Yes to group delusion, but I feel the same way about many things - climate inaction, the state of democracy, how well-served the average person is by neoliberal capitalism, politics
It sounds like you might be a newer vegan, in which case 1) congrats on making the change - it's great you're here!!! and 2) I want to mention that anger like you might be experiencing now (eg, wtf is wrong with carnists) was a strong emotional reaction that I had after becoming vegan that I didn't see coming and that passed rather quickly. (I'm foggy on the timeline but I recall the intensity wore off after 6 months.)
For example, I have a vivid memory of sitting in a small university class. The class material involved minor mistreatment to a dog (eg, left in a car in a parking lot, no window open for 10 minutes), and my classmates - all of who were omnis, some of whom were eating meat products at that very moment - got so up in arms. I thought "wtf is wrong with you people? How can you see comparably sentient beings in such polarized and incoherent ways?"
In the same way that being vegan takes food skills that are learned with time, I think the same is true with psychological skills about living in a world that we might see as sick and unjust.
The way I see it, it's often easier to do what is popular even if it's morally wrong than to do what is unpopular even if it's morally correct. And as animals we're programmed to do what's easy. I think what's unique to us as humans is our potential to reflect on things and to choose to do what's right over what's easy. Our society doesn't value that type of behaviour.
I think doing what's safe and easy is the main reason why people eat meat, and every delusion is in service of fighting off the cognitive dissonance between a) seeing themselves as good people (something we all want to think) and b) frequently doing something that on some level they're not comfortable with.
You can't reason someone out of a position they didn't arrive at through reason. I also don't think you can shame people into changing against the grain of what's easy. I've converted one person to veganism. And I wasn't trying to. We were friends and they brought up the subject of (I'm paraphrasing) "why love one and eat the other" (e.g., dog vs pig/cow). I think I offered them a pretty safe space to think about it and I shared my perspective in a very non-judgemental way. Weeks or months later (I can't remember), they came back to me and said "I went vegan soon after our conversation, and I feel great, and it's been easier than I expected so far." I don't think I could have done my part there unless I was non-reactive and non-judgemental. I think the crucial ingredient is that they had the courage and resources to confront their dissonance and re-evaluate their position.
You're not crazy, you just live in a crazy world. It gets easier with time, and vegan social support and other resources help too