Also, was Korriban supposed to be a well-known planet? I always got the impression that it’s location was kind of a secret.
I believe that was the original intention. But once later writers retconned the planet into the original Sith homeworld and capital, that went straight out the window. Skimming through the Wookieepedia article, it even mentions that the Republic invaded and held the planet for brief periods of time.
And I’m sure they could have made up some decent lore excuse for why you wouldn’t want to “nuke” a dark side planet like Korriban or Dromund Kass.
And they should have, 'cause otherwise, it makes the Republic/Jedi look foolhardy.
Besides, didn’t the Jedi think they killed all the Sith? So why even bother?
To remove the possibility of some ambitious Force-wielder stumbling on the site and making use of the knowledge waiting there? Dark Jedi and other non-Sith darksiders still existed in the period the Sith were believed to be extinct.