This is a very specific question, and it might be easier to answer it completely yourself, but I can give a bit of help!
These metaphors are negative ones, and the question is essentially asking, 'Which groups in society or at your school are targeted and made fun of?'
How it's received could be written from the group's POV, explaining how hurtful it is to attack a group, especially if it's doing nothing wrong. What could be done to change it-- well, a common thing is to increase awareness about the topic the group is representing.
I can't really give any specific examples without getting too political, but I do hope this helps you develop one!
