The fourth word on Tether's wikipedia page is "controversial". Nobody is under the impression that it's fully collateralized. Would you care to make the case that a different, trusted stablecoin isn't fully collateralized?
DAI specifically is collateralized with ETH using smart contracts - it's over 100% collateralization is incontrovertible.
Your concerns about network trust are entirely unwarranted. In the bitcoin whitepaper published over ten years ago, before the software was even written, Satoshi explains how a trustless network might be created via Proof of Work.
On the topic of price fluctuations, I'd like to point out that not only are there a plurality of stablecoins pegged against and collateralized with dollars, there are also synthetic assets like DAI which follow in Satoshi's footsteps - using game theory, economics, and finance, to novel and practical effect.
I highly recommend reading the Bitcoin, Ethereum, and DAI whitepapers (in that order).
Have you read the original memo with the citations intact? Gizmodo published an edited version. I would agree that the memo reads like a series of bigoted conjectures if you read the edited version.
The analogy works even better because organ transplants are sometimes necessary and sometimes not. Although GP started off defining a binary, I don't think they are thinking in black and white. A charitable reading of the GP implies the nuances you express.
Not to be pedantic, but...