My theory on this is that the Red Matter black hole that Spock Prime created gained in size by way of consuming the sheer energy of the supernova, thus enabling both Narada and the Jellyfish to pass through. Also note that both ships were very state of the art for their time, so they were within their means to traverse the black hole reasonably safely.
The black hole that Nero had his crew create within Vulcan's core did not gain much in energy compared to the supernova, and therefore remained the size of a very powerful peanut (equal to the size of the amount of red matter separated from its larger whole at the Jellyfish), which then sucked the planet's very unfortunate contents into it, maybe letting the contents in their basic and compressed form be ejected at whichever other side, as if passing though a one-hole meat grinder.
