But from the scientific perspective, there is a specific factual question: what are the effects of meat consumption on human health? Nutrition research is super finicky. Even absent any conflict of interest, it's unclear that nutrition results are trustworthy. So I don't think it's fair to throw out every study which says meat is healthy and just focus on the studies that say meat is unhealthy.
Person A sees someone torturing a dog and kills them out of indignation.
Person B is a hitman-for-hire who doesn't know who he's killed or why.
Are person A and B really morally equivalent?
That's not what we're talking about, however. We're talking about what level of suspicion is appropriate in various scenarios. It's unlikely we can _know_ if results were purposefully sabotaged or not. We have to make some best guess. Interested parties funding studies is deeply suspicious, and should be treated with a hefty dose of skepticism. Hand waving that "maybe the researchers were motivated by empathy?!" is not at all equivalent. That is a incredibly low bar that, itself, undermines trust in science, as one could trivially make up similar excuses to distrust virtually any study ever conducted. Oh, researchers found declining sources of fresh water year over year? Biased. They probably just like cheap drinking water. Better ignore it. An Aquafina-backed study shows the opposite. That study is biased, too. But they're both equally morally reprehensible.
Not everything has to be a both sides equivocation . Degree and severity matter. "Compassion for animals" and "receiving funding from a party with a vested interest in the outcome" are not equivalent conflicts of interest.