Ra-Den is definitely way easier to beat than a lot of other HC bosses in ToT.
As others have said, he was not meant to be the toughest mo-fo eva!
I'm fairly certain that if Scrubbusters doubled or tripled their time to get to the level of the other top 10 teams, then they'd be able to compete for the first spot, but they're not super hardcore, they're just very very skilled. At least from my perspective.
"God damn you all. I DIDN'T SAY THAT CONTENT IS TOO EASY!"
Yes you did. You clearly stated that Raden is faceroll. Faceroll means too easy.
Also to OP. Next time do it when your group is average 528 item level.