that's not any different from when Apple released developer previews of Lion and iOS5. Are we seriously arguing over the 'finished' state of a developer build? Really?
No, what is being discussed is using a developer build of a very alpha-state software as a comparison point against something released that has tens of millions of devices in the market.
Gruber's argument started out as a criticism of Paul Thurott's comment that Windows 8 was the death knell for the iPad, but then he goes off into comparing Microsoft's and Apple's corporate release strategies... The criticism of the "Windows 8 kills iPad" comments is fair, but trying to group these tech pundits under the 'Windows' banner and use it to criticize Microsoft as a company is faulty logic at best (and purposely deceptive at worst).
15.2 Apps that depict violence or abuse of children will be rejected
16.1 Apps that present excessively objectionable or crude content will be rejected