Unfortunately the author didn't do basic diligence on that intro - anaerobic photosynthesis is indeed a thing and was likely around for about a billion years be

Unfortunately the author didn't do basic diligence on that intro - anaerobic photosynthesis is indeed a thing and was likely around for about a billion years before the water splitting component evolved (such anaerobes get their electrons for photosynthesis from sources other than water, such as reduced iron in an anaerobic ocean). All the author had to do to check this was type 'anaerobic photosynthesis' into any search engine. (Add 'banded iron formations' for some really interesting stuff). So if you get something like that wrong, and it's the analogy at the heart of the argument, well... it does make one question the accuracy of the rest of it.