Why does Daito only believe they should only live their lives on the oasis?

Shoto comes to Parzival's stronghold and tells Wade that his brother, Daito, was killed. Shoto explains that he and Daito were not really brothers, but friends who met in a support group several years ago. They chose to become brothers in OASIS when word of Halliday's egg became public. While Shoto was getting the jade key, Daito remained outside to watch for Sixers. The Sixers arrived and Daito used an artifact to transform his avatar into an old television character called Ultraman. The Sixers were battling him and losing when suddenly Daito logged out of OASIS. Shoto believes IOI employees broke into Daito's apartment and threw him over his balcony. Shoto shows Wade both newspaper reports of Daito's death and the video of the fight on Frobozz. Shoto then vows to keep fighting in order to get revenge for Daito.