People make unnecessary assumptions and that causes them problems. When I took active part in various Keto and LCHF communities, I volunteered to help with that. No, you can't just eat bacon. No, carbohydrates aren't forbidden, but merely limited. And so on.

I remember some active folks helping people who didn't want to eat meat learn how to eat Keto without meat. Some of them even managed not to be stereotypical vegans. 😉

And I'll tell you what I've told everyone who has "well, ackshually"d me about CICO: yes, but sugar seems to cause most people most of the time to struggle with limiting food intake, whereas fat tends to do the opposite for those folks, so eating more fat and very little sugar helps them play the game on easy mode. This is an effective way to transform eating habits. I was one of those people. Eat fat xor sugar, for the folks who understand Boolean.

And I'll point out three things:

Studies that purport to study and debunk low carbohydrate eating routinely choose limits for carbohydrates higher than what Keto and LCHF actually eat, which renders them inconclusive regarding what we actually do. Some of them, for the sake of simplicity, feed subjects fats in a way that no human would, which avoids the benefits of eating a variety of whole foods, which Keto and LCHF approaches recommend.
There's no guarantee that the health problems introduced by extensive Keto/LCHF eating are worse than the health problems that accompany an extra 20-50 years of obesity. Neither "side" can be sure of its stance here. In particular, cancer comes for us all, in one way or another. In many ways, life is becoming an exercise in ensuring that cancer gets you instead of some other disease. 🤷
Many folks, including me, report success using Keto/LCHF as an intervention rather than a lifestyle. I can report that I changed my eating habits radically so that now, even when I'm not attentively restricting carbohydrates, my default choices hurt my body less than they did before Keto/LCHF. I think that's why I've regained 40 pounds instead of all of it.