User blog comment:B214/Volume 21 info & spoilers/@comment-187.209.22.243-20160217145113/@comment-1359322-20160217153914

I think people misunderstood the purpose behind Sirzechs' team. As seen in V12, for safety purpose, Maous are usually asked to stay behind the scenes and leave the fighting to their subordinates, hence Sirzechs prepared a team that can counter Rizevim without him. It's not that Sirzechs or Ajuka can't beat Rizevim, in fact they can probably do so easily but they usually aren't allowed to take action due to their position as leaders.