The mention of security holes seems to be the only real serious critique. Hopefully some urbit people could address those, since claiming to be a secure personal VM and just exposing your data on disk to the cloud provider is crazy.
Other than that, the author seems to be mostly making fun of urbit for being weird and alien, which is strange because its goal basically seems to be weird and alien. This is actually quite excellent. Computing needs fewer javascript frameworks and more truly weird and alien shit, with a healthy dose of NIH.