A question about hen 10 episode change of face

[Gwen Tennyson]

In Ben 10 episode change of face, why did the juvenile detention lunch lady did what she did to Qwen food when she was in Charm Caster body, that was very extremely cruel, she never even seen her before, do most juvenile lunch ladies behave this way, and did Charm caster really deserved what the other two inmates did to her at the last scene of the episode?