Sure, if you define AGI as needing to be able to perform all physical tasks that a physically median-or-better adult human could perform, maybe it needs to be embodied essentially by definition. I don't think the physical aspect is implied by "artificial" or "intelligence", and I would argue not by "general" either seeing as how it's modifying "intelligence".

Also, think about humans who cannot accomplish physical tasks of this standard. Babies, elderly, disabled, malnourished, and maybe people who are just really lazy or defiant.

I stopped reading at this point so sorry if the essay returns to this point and addresses it.