I've been telling everyone this for years, and Remo's QC issues (and their denial that they even had issues) were the reasons I stopped using their heads.
As for the tap test, Aquarian didn't invent that. Every savvy drummer - Roy Burns included - had to test plastic heads to make sure they had a tendency to resonate. It meant that the Mylar is evenly glued and is not wrinkled (and in the case of 2-ply heads, it is crucial that the plies lay flat against each other!)
The difference between 'good' and 'bad' heads is most evident on toms, where a nice decay is normally desirable. Snare heads are more forgiving (as they're not intended to resonate the way a tom does,) and bass heads also tend to mount better as there's more area and manufacturing anomalies affect the sound to a lesser degree.
I would say that the article's bad head claims of 2/3 or even half are a bit extreme, but I personally had a failure rate of about 33% with Pinstripes and Emperors. That is, more often than not, at least one of my three toms didn't sound good thanks to a bad Remo head.
Bermuda