... What is going on? Yes, that's what it means, that's why I used it. Notice it does not say 'lie' or anything directly synonymous with lying. It's related, sure, but not the same.
You can tell that it's not synonymous with lying because had you said to me "are you saying they're lying?" I would have said 'no'. This is always the case with semantic disagreements: if you want to know if someone intends a certain connotation, you can ask if they would agree with a rephrasing.
The disingenuousness is presenting a non mainstream theory as if it is fact. Anyone reading that initial comment probably has no idea whether "cholesterol and statins are suspect science". Had they said "some people think they're suspect science" there would have been nothing wrong. To claim they're suspect as a fact is disingenuous: it could be true, or it could be that the person posting it is one of those anti-establishment nuts who disagrees with consensus science about everything out of conspiratorial distrust and is constantly smuggling that stance into conversations all over the internet. Since it is very easy to present the state of affairs in a forthright manner, the only reason why someone would present them deceptively is (presumably) something like that. Hence knowing that the view is not mainstream is very useful for evaluating the motives of the original poster.
It's not evidence that they were lying, because that implies intent. No, probably they believe what they wrote. But it's evidence their ability to reason is suspect and possibly corrupted by some ideological motivation and so should be taken less seriously.
Not that I care, really, about any of this. Mostly this kind of antagonism is very frustrating and it's just kinda cathartic to try to shut it down.
My suggestion is that instead of engaging with commenters with your "oo! Logical fallacy! You broke the rules of arguing!" stance you instead try to find some way to productively engage with their actual thoughts. Perhaps figuring out why they said what they said instead of assuming anything you do not understand is a sign of a weak mind that needs to be corrected. You'll find people respond much more warmly to you if you do
