The Snow Crash bomb was not part of Rife's original plan; the original plan was to cow the world's hackers with the threat of Snow Crash.
But he can threaten us with the blunt instrument of Snow Crash. That,
I think, is what happened to Da5id. It may have been an experiment,
just to see if Snow Crash worked on a real hacker, and it may have
been a warning shot intended to demonstrate Rife's power to the hacker
In order for Raven's use of Snow Crash at that point to be a successful warning shot, he needs to use it on a well-known hacker. He first tried to tempt Hiro (calling him by name, suggesting that Raven had been briefed on who to try to use Snow Crash on), and when Hiro declined, Raven tried Da5id next.
After Rife's plan has failed, due to Juanita's release of the nam-shub, all Rife and Raven have left is revenge on the hackers (Juanita's community) by using the Snow Crash bomb.