You seem to have a deeply intuitive knowledge of blockchain tech, and you've posted with a throwaway. I'm assuming you are a well known member of the community.
At risk of being petty, no, they don't and aren't. See sibling thread: they're not disputing the core point I raised (that PoW schemes are not immune to being weakened by forks), but changed the topic to different one and seem to have copy-pasted general arguments in favor PoW. (It's copypasta because they have a cryptic reference to a poster on a different forum, /u/nullc that doesn't help us find the argument here without searching their history on reddit [I guess.])