I doubt they could really do any legit damage in "the wrong hands", Mig 21s, 25s, 29s and so on are available on the private market, and those are all supersonic platforms.
I take it as more along the line of Raytheon's decision to shred the Beech Starships. It's a CYA move so they can respond "Well, we did our best" to avoid a phantom potential lawsuit.
Would you like it if the P-51s, B-25s, etc were ALL shredded at the end of WWII so they "wouldn't fall into the wrong hands"? If there was justice, then I'd be able to take my kid to an airshow 15 years from now and enjoy seeing a couple of F-14 Tomcats flying by as part of the Confederate Air Force.