And reviewers are afraid to lose their freebies so will hold back negative statements or soften them.
The problem I found was that all the games revewied were linked in an affilaite sales agreement.
This created a 'bubble' of games that many reviewers reviewed.
Searching further, I found that board games are so loved by millions that you can find quality reviews from peoplw who buy many games. You can even find views of the full contents of games so you can make a further informed decision.
None of this was on social media, just a good old fashioned web search.
BGG does have a very clear bias against traditional games (see Clue, Monopoly, etcetera), due to it's roots, but that's changed a bit as board games have become big again.