If he describes in granular detail how user profiling and ad serving works on Facebook, then Facebook is going to take the hit on practices that are basically industry standards. If he obfuscates, and focuses on FB controls then he seems like a liar.
If he explained how ad-tech works across the internet then it would look like whataboutism and him invoking the bandwagon fallacy.
At the end of the day it seems like someone/some company is eventually going to take the fall for the whole ad-tech industry and cause major reform - is Facebook the one who's going to take the arrow?