The article goes on to point out that their theory about copy-on-read being the problem didn't pan out, because when they disabled refcounting on code objects s

The article goes on to point out that their theory about copy-on-read being the problem didn't pan out, because when they disabled refcounting on code objects shared memory usage didn't change. It then goes on to identify the real culprit, which was GC. So, no, this article is not an excellent argument against reference counting.