That sounds like: “we know there are short term benefits of quitting smoking, but we’re concerned about the long term risks associated with nicotine withdrawal.”
The fact is, it’s popular rhetoric to say “we just don’t know” to discourage people from following a ketogenic lifestyle, even though no one can produce any evidence or examples of whatever it is they’re afraid of.
We do, however, know what the long term effects of T2D are. So I’ll take my chances with the imagined dangers perceived by a vegan trying to come to terms with the idea that he may have got it all wrong, and focus on the fact that whatever it is that takes me out of this world, it likely won’t be: diabetes, heart disease/attack, or cancer.
My money is on getting hit by a bus while crossing the street, not paying attention because I’m checking topics on this forum.