The point is that this article conflates several things and is describing some fairly outdated or inefficient obfuscation techniques of which launderers would be some of the users of.
It goes from Hydra market duffle-bags of cash hiders (lolwut), to chain-hopping and scant mention of privacy coins. It randomly talks about Wasabi wallet same-chain bitcoin mixers, and then talks about Bitcoin Fog's operator being arrested which is much much older technology. It doesn't acknowledge or provide awareness about people actually wanting the privacy coins to begin with or staying within the mixing system (or trading claims to assets in the mixing system), and just assumes people are trying to obfuscate briefly with the end goal of holding non-private coins or fiat.
I don't get the impression that they were avoiding describing useful techniques for criminals, I get the impression that they have no idea.
