I'm not sure what more you want from him, there are many papers and even a textbook linked?
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
well he certainly mentions a result where if there is an everywhere timelike Killing vector field (+ some other assumptions) you can prove that Hawking radiation doesn't occur and that does not include for example the Schwarzschild solution because the Killing vector field partial/partial t becomes non-timelike on the horizon.
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.
> 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?