They are not called thieves or robbers in
John. Only in the Synoptics.
Simon of Cyrene isn't a thief or robber, yet in the tradition of Basilides he is crucified in place of Christ.
In all of the canonical Gospels, Jesus makes these statements:
And who ever does not take his cross and follow me is not worthy of me.
Then Jesus told his disciples, “If anyone would come after me, let him deny himself and take up his cross and follow me.
And calling the crowd to him with his disciples, he said to them, “If anyone would come after me, let him deny himself and take up his cross and follow me.
And he said to all, “If anyone would come after me, let him deny himself and take up his cross daily and follow me.
Whoever does not bear his own cross and come after me cannot be my disciple.
Under such requirements, this makes the two robbers crucified along with Jesus worthy of being his disciples.
There may be an interference with the
pseudo-Josephus figure, who probably imposed the robbers rampant during the time of Claudius into the Jesus story. Making all theological musings about their significance entirely meaningless.