It's bloody John Baez, the man knows his stuff.
On you actual point, it is shocking because its claimed that baryon number is not conserved without black holes getting involved
Isn't it also speculated that there's hawking radiation caused by the event horizon at the edge of the visible universe in an accelerating frame?
So for example if you take a dead star in a vacuum with nothing else in the universe (and make certain technical assumptions) then you can prove that the star does not emit Hawking radiation. That's quite a strong result, and certainly does make the result seem shocking.