There's a fair number of case studies that aren't suitable for peer-review. But in those cases, just publish the data openly for analysis. This "study" didn't do that, and had a lot of other issues mentioned in the comments here.
So your intuition wasn't wrong here, but overall, you may be discarding a lot of relevant case study work due to over-reliance on the peer-review process.
I unfortunately submit stuff for peer-review and do case study work, so I know a lot about both sides of the garbage aisles. Lot of crap makes it through peer-review, and a lot of good work never does because of cronyism and single-blind review.
So your intuition wasn't wrong here, but overall, you may be discarding a lot of relevant case study work due to over-reliance on the peer-review process.