Indeed you linked to a PDF with 25 pages of main body text, and I generally come here for the comments. I can just as well respond to your excerpt, as it is clear to me the implications of such an attitude. If you view all activism as folly and encourage others to do the same, you can be quite assured that those who do choose to influence the world will have more success in your absence.
I am happy to respond to any specific questions you have (even with excerpts) but I am not here to read a 25 page PDF. And as an aside, I see in the author's conclusion that they are wholly dismissive of Karl Marx, which I view as a serious error. I suppose the author is not familiar with the excellent work of modern Marxist intellectuals like Richard Wolff and David Harvey who have quite effectively applied Marx's original works to modern day economic analysis. If the author were familiar with their works it would be clear that modern Marxist intellectuals view the 20th century not as a complete failure of Marx's theories, but of the application of those theories in the hands of the centralized state. When applied with coercive violence those theories lose the very democratic power they had hoped to capture and give way to human greed and demand for accumulation of power. We can nonetheless learn from Marx's analysis of the problems of class-based society and the benefits of worker or community control of the means of production. As Wolff and Harvey repeatedly explain in their work, the task is not to dismiss Marx's analysis but to learn from 20th century experiments of the importance of democratic control. As a practical example, Wolff's primary takeaway from all this, informed by the desire to reduce the importance of class and expand worker based control of production, is that we should aim to move our economy to one where firms are more predominantly worker owned. That we would move from top-down managed firms to worker-managed firms is a well founded and reasonable argument that bears no resemblance to Stalin's USSR, for example. I don't know if the author balances the arguments of pro-Marxist and anti-Marxist intellectuals or simply chose only to look at one side and believe they had the full picture, but it only reinforces my belief that if someone advocates for a depoliticized society, they will simply favor the status quo.
I would encourage reading or listening to the words of people of color and other marginalized groups to ensure that any prescriptive views of society you hold take in to account the different ways that marginalized people experience the world. You mentioned you are interested in holes in Huemer's logic, and that is where you will find them.