Until a few months ago, for instance, the Automatic Differentiation Wikipedia page had been gutted by someone looking to publicize their generally uninteresting pre-print on arxiv.
I wonder to what extent it is that perhaps Wikipedia draws editors of a certain leaning (much as some professions seem to - on both sides).
Whatever, it's incredibly frustrating when you see the framing and feel the umpires are also often in the same bubble as the editor pushing their position on the article.
Why do you hesitate to say that the left are causing a problem?
But how does all that even relate to the question of Jimmy Wales' seat on the board? The board doesn't moderate individual articles.
A primary concern of the 'politicization' of information is frankly the commitment to rigour and objectivity of the leadership cadre, who are often lacking in self-awareness with respect to these issues.
I also know that the optimism and perhaps naivete was the better patron. Random vandalism of some pages wasn't even a large issue, but we can see severe framing in many cases and especially hot-button topics are often unbalanced.
Best articles come from random individuals from all over the planet. Certainly not from the WMF, but also not necessarily from a dedicated community.