Seems that bcrypt, scrypt and Argon2 are all designed to slowdown attacks on specific hardware platforms. All run relatively slow on GPUs so they all work. The blog covers how to overcome this using FPGAs, specifically for bcrypt. The same might also work against scrypt and Argon2 if configured parameters are in favor of FPGAs. If parameters exceed the specs of FPGAs, they will be slow as well. So depends on the configuration of the algorithm.
I guess he's feeling the heat of sites that do more than parsing emails from SPAM lists. These sites include full cracked passwords, HIBP 2.0, see e.g. https://scatteredsecrets.com/.
So they've scraped public data. Why care?