Think the writer is referring to the restaurant facing side of the software and not the user app/website. Those are much nicer.
[1] There are issues in all software (bugs, lacking your pet feature, etc), and people like to complain.
[2] The article's author has developed a product in the same space (although it seems to be more of a restaurant website template, rather than a reservation system), so there might be some jealousy there.