1) The reviewer may have had similar work and wanted to hold up the publishing of OP’s paper while finishing their own work. Or there’s some personal animus. Or OP’s paper may have threatened to surplant the reviewers work. There’s a whole plethora of reason for a particularly hostile review. It’s a big enough problem that my partner who’s going through grad school now had the option of requesting specific people NOT be on the reviews for her (first publishing in gradschool as a first author!) paper because of scooping, animus towards her PI, etc. that may have resulted in an overly hostile review.

2: because his non-temporary account is not connected to his real name?

1) My first publication in the topic, iirc. The only reason I can see them doing this when all the other reviews were good was eg. They have grant applications underway and feel undermined, or they are petty and don't want their own technique to look bad etc. (the extreme roadblocking and 'I won't let you compare performance or accuracy against other techniques!!' is a little telling imho...)

There are a lot of people out there who think a field of research and all the money in it belongs to them.

And there's some angry people who have effectively no power or influence over their own everyday life that act like little tyrants when they get to review papers.

(fwiw, I coauthored (1) without any grant support, just for fun, and don't think I ever applied for a grant in that area? I can't remember).

Who knows? Trying to figure out hostile reviewers is a guessing game and not very helpful for your own happiness

2a) travelling on holiday, posting from my phone.

And

2b) this has personal identifying info and I can't remember everything I've ever posted on my other account right now, (or even the u/p for my desktop account, haven't posted in months)

P.s. Glad you enjoyed it, I've been looking for an excuse to mention that story for years :-)