Uh, a "case study", by definition is the analysis of a single case.
The problem is not that you cannot draw an accurate conclusion, but that you must acknowlege the limitations of the study, just as you must do with any study. It is standard research methodology.
Of course, there should also be citations of other supporting and dissenting research by others, if it was real research. But it was just a post, believe it or don't. Or even better, do some of your own research and report back.