Exactly what the reviewers were pointing out.
No, they weren't. I can read English as well as you, conceivably even better, and that isn't what they were saying. I quote here:
"Far from denying the validity of Bengtsson's questions, the referees encouraged the authors to provide more innovative ways of undertaking the research to create a useful advance."
In plain English: he did point out real errors. They don't deny that. They just don't like the way he did it.
They encouraged Dr. Bengtsson to find some error that they could publish. Instead, he just pointed out that three things that ought to be different were in fact different. That is not useful.
No, they said that the errors he pointed out were not "helpful" to them, and that he did not sufficiently explain, to their taste, what the cause of the errors were.
However, that position is not a scientific one. The cause of the errors is neither his concern nor his responsibility. Pointing out the presence of errors is important. Taking an arrogant stance against apparently valid dissent is not. I repeat: this is supposed to be science, not a social club.