There is no such thing as an impartial sponsor; some are more obviously biased than others, but the belief in a fictitious impartiality is part of the problem. It shouldn't take a meta-study for people to see am obvious conflict of interest.
I'm biased. You are biased. Everyone is biased.
I guess I didn't communicate my point effectively. I wasn't trying to nitpick semantics. I was trying to say that people don't think critically because they assume impartiality.
If the first thing people did when they looked at a study was to ask what possible biases or conflicts of interest the sponsors have, then conducting a meta-study concluding that biased studies are biased wouldn't be news to anyone.