"Researcher's Bias" is almost always going to be an issue. I always start seeing red flags when someone opens with something like "we set out to prove that white vinegar kills XYZ viruses."

OK... you've already predetermined what you want the outcome to be, so now your methodology, sampling and wording will automatically skew in that direction. And that's before we even get to spin. "Lying with facts" is a time honored tradition, sadly... because everyone has an investment in their opinion; nothing is left to simply be information.