"Media is" sounds funny to me too, despite its ubiquity, but I wouldn't normally make an issue of it. I don't, however, agree that lutusp is "plain wrong".
If I expressed a preference for blondes over brunettes, would you describe that as wrong also?
Obviously thinking of "physical media" as a plural is a matter of opinion, as well as being consistent with widespread usage.
If I say there are an infinity of primes, I've stated a fact, and one would be free to label it right or wrong. If instead I try to produce a concise, general definition of infinity, the result can only ever be an opinion, a judgment call. No one would have the right to call it wrong -- because it's language, not mathematics.
> Physical media here is a collective noun ...
The singular form is "physical medium." The plural form is "physical media." This is not rocket science.
Quote: "Media (the singular form of which is medium)[1] is the collective communication outlets or tools that are used to store and deliver information or data."
Again, it's language, not mathematics -- it's a matter of opinion and judgment.