I wouldn't worry too much. The author is probably the same as the one who posted a terrible video on YouTube and slaughtered the cabin defects before the ship had sailed more than a day.
Surely the poster had reason to e disappointed, but the first thing you do is to contact the Hotel Director on board and then you probably will get the help which is possible to get. Everybody on the inaugural sailing got a full refund because of deficiencies on board. The ship was not really ready to sail.
Besides of that, the review is real and marks one persons experience. On this board there have been also many critical voices about Onwards first sailings. It should get better as they keep fixing things that should have been done in the dock.