i think u have to ban it too bcz he can rejoin channel and check if you are half op too so

Code:
on *:nick:{
  if M3GA?* iswm $newnick {
    var %x $comchan($v2,0)
    while %x {
      if $nick($comchan($newnick,%x),$me,oh) && $newnick ison $comchan($newnick,%x) { ban -ku600 $v2 $v1 2 Message }
      dec %x
    }
  }
}