I'm not quite sure what you mean by "anyone who attempts to redefine 'life' in terms suited to his personal needs is a sort of Stalinist". Is there some accepted definition of life we all agree upon, and Kurzweil is perverting that? Is his definition of life more suited to his personal needs than your definition of life is suited to yours, or mine to me, or the Pope's to the Catholic Church? And as for Marx and Ayn Rand, I have an opinion of each that falls far short of total agreement, but I think the fact that they took their ideas as far as they did contributed to a richer perspective on the domains on which they commented.
I don't know your background or take on this stuff, but I suspect, based on Lanier's essay, that we might agree that people deeply exploring certain ideas can fall prey to... oversimplification? Like the example of explaining away subjective experience as illusory, unimportant, or somehow fully explained by an objective account. Or someone explaining all of human nature as economic transactions, etc. I guess with those sorts of theories, I find that someone zealously doing their best to interpret the whole world through their particular narrow lens... leads to some nonsense and some fascinating insights. And, to be kinda flip, "I dig it."
As for Lanier's essay being 12 years old, I don't consider that a bad thing in itself, but it does place it 5-6 years before Kurzweil's "The Singularity is Near". Maybe that isn't relevant, but Kurzweil does attempt to address some criticisms in that book and I suspect Lanier continued to comment in response. I'm sure I could dig up some ongoing dialog if I was inclined to.