It begins by saying that hiding your beliefs “is lying”. I’m pretty confident that the sort of belif-hiding being discussed in the post is not something most people would label “lying”
Hiding your beliefs in ways that predictably leads people to believe false things is lying.
Deletionism and inclusionism, and a lot of problems with Wikipedia in general, are related to people with OCD editing Wikipedia. People with OCD are going to be very reluctant to not apply a rule 100% of the time even if the rule itself describes subcases where you’re not supposed to apply it 100% of the time.
This is on top of problems with people using deletionism or inclusionism as excuses (because it’s a lot easier to get your way if you can point to a rule). And the political bias, which is real to the point where you should not trust anything on Wikipedia that is a live political topic on the Internet, because there will also be such people on the Internet editing the Wikipedia article and it’s a tossup as to who wins.