Everyone in the world has been slaughtering each other for millenia.
Think of it this way - which history of the American Revolution is more accurate, the American version or the British version?
Etc.
Everything has degraded terribly in the last 5000 years. Populations slaughtered and dispersed, civilizations destroyed, cities drowned under water and covered with jungles, histories forgotten. After the war of Kurukshetra, it shortly went downhill all over the world.
Good thing we won't have to face another End Of The Glaciers event for another 100,000 years.
Note, Dwarka was recently discovered underwater ~ so it was an historic city right where the Mahabarat said it was ~ but a little offshore.
These things happen even without sealevel change. In fact, ancient Alexandria was found just a couple of decades ago ~ offshore!