As far as I could determine, the issues in the second point do not exist.
See the actual WHO report [1] from 2019. Page 8 contains the recommendations about "sedentary time" for infants. The box is literally tagged "Strong recommendations, very low quality evidence." The paragraphs at the bottom of the page contain a summary of the evidence from the literature.
I don't see any basis for anti-science thinking in this article. It seems like you may have only seen/read the executive summary page viii.
The UN's page of accomplishments [2] lists plenty of work that you don't have to be an optimist to find value in (e.g., support for refugees, food aid, and vaccines).
[1]: https://iris.who.int/bitstream/handle/10665/311664/978924155...