Were Revan's actions justified?
Let's look at the facts. He loses his family, friends, and everyone that ever cared about him, some of his closest friends are murdered before his very eyes.
Pretty sure he was aware that his wife and her life was wasting away while he was locked away for 300 years, and by the time he comes back, Satele isn't even recognized as his great great great granddaughter, he's gone insane, and also, HK-47 is killed.
It's like everyfhing he ever did was all for naught.