Or, does this favor the argument that Peter, who has just had to be whapped upside the head for limiting his understanding of the grace of God toward salvation, has now learned better–but may still be not understanding (or accepting?) the full extent of the grace?
(Hint: does Peter ever have to be whapped upside the head again for limiting his understanding of the grace of God toward salvation? I seem to recall that he does… )
Of course, Peter might mean there that God has shown him (or so he thinks) that he should not call any man impure or unclean simply for being of another nation or ethnic group. That would comport with his later statement of belief (reported in v.34) well enough.
On the other hand, the vision itself could be construed as universalistic in scope (though easily misunderstood as meaning something less).