But for me it’s EOT here, since you can’t argue against a believe system.

That is exactly the problem, you brought your belief without evidence and there is no way to persuade someone out a position they 'believed' themselves into.

And if some funny thing like Clostridium difficile comes knocking I’d rather have a diverse microbiome so there is no space for it, that’s all basic and boring ecology.

This is actually a fun myth! zero-carb carnivores have a very diverse gut microbiome. We have posted about this before - https://discuss.online/post/39760974 - [Paper] Long-term adherence to the carnivore diet and its impact on the gut microbiota: a cross-sectional study - 2026

The issue is that the literature really doesn't understand the mechanisms of the gut microbiome at all, it's early days - the publication is mostly observational and associative. Lots of assumptions are being made.