"Chief marketing officer of Unilever" isn't the guy running experiments, he's the guy that hires ad agencies and auditors that in turn have teams of data scientists running various experiments for Unilever.

I guess you could propose a conspiracy theory that all these people are conspiring to put together fake reports and data sets, but that sounds extremely unrealistic - ad agencies are essentially money-counting businesses like banks, and they take data security very seriously. (Because usually they'd be audited at every step.)

In short, smart people have already thought about these issues, and there isn't any inherent pro-advertising bias in industry, rather the opposite.