I think it was obvious that Yushin could have continued. He took the easy route against an elite fighter. Just being smart thats all.
Anderson when he faced Yushin wasnt considered elite your arguement is just false. He back then in his last 3 bouts beat Rivera ,some guy called stout who i saw get his ass handed to him in cage rage and a loss to Ryo Chonan and few fights previous he was submitted aswell.
Anderson stunned him badly with and illegal upkick and then tried to get back at Okami afterwards , Yushin was in no state to continue and Anderson was DQ justly.