I can completely agree (especially if we went back to analyse footage from pre-2000 there would be pretty stark bias at play with hindsight.
But when I think of commentaries I've heard, I've not noticed a bias or many commentators clearly having a dislike for a particular player - regardless of colour. Plenty of commentators show themselves up and to be crap at the job, but not biased outside of the normal Top 6.
If the PFA want fans to take that survey seriously, they need to better highlight which commentators where looked at, what games, what season's, the bland % of black/white/ethnic in the game as a base point for expected praise/criticise across the board and also what descriptions they decided were racist.
Prove all that, show the details and if it is subtle or stark, I'm sure plenty would take a closer look and decide for themselves.
Unfortunately, that report makes even liberal me go 'oh, so now this'.
So I look forward to reading this -
https://runrepeat.com/racial-bias-study-soccer - on a scan it gives some of the details you'd want.