That’s… really not true or at least not as dramatic as that statement makes it sound.

Those “special workstations” are mostly about lack of features they view as potential attack vectors (external or internal motherboard ports, replaceable/non-soldered components, thunderbolt, anything extensible or “repairable”) and mandate certain hardware features (hardware tpm, locked secure boot, locked UEFI). Other than that, those workstations are Lenovo, Samsung, or Dell machines running typical chips. They may pick certain CPU models or chips but that’s mostly about avoiding new or “cool” features that may not have matured enough yet. Most of them are moving to thin clients though. Where you use that “special workstation” to remote into an VM that can access production systems. And that part is partially about controlling the software running in the VM and making sure updates can be forced “offline” on the VM even if you haven’t connected to it in few weeks.