This is crap science from Harvard. If you go to the source, this was entirely based on talking to people on social media.

There was no control group, not even an experiment group who were asked to change their diet.

So tjey ended up only talking to people who changed their diet voluntarially (probably because they expected health improvements, which introduces a huge confirmation bias), and then talked about it online (which they're more likely to repeatedly do if they feel they had a positive change).

That doesn't mean the carnivore diet is bad, or even just neutral. It just means that the supporting evidence for it is merely anicdotal and comes from people being very loud on the internet.

I'd welcome a study where people only change their diet based on being told to because they are in the study and they don't know what effects it might have. They should take objective measurements like A1C, iron, cholesterol and other bloodwork. Then we could have some real evidence that it's worth more studying. It can also include subjective things like how people feel, but having something objective is key.

The moral of the story is that if you're going to promote this intenet survey, your point should be that scientific research is needed to confirm and quantify the health benefits.