What clues do you have that people were not kind to the narrator?

The narrator in Rodman Philbrick's novel Freak The Mighty is Maxwell Kane. He is a learning disabled kid who is a gentle giant. He lives with his grandmother and grandfather because his mother is dead and his father is in jail. 
One example that people are not kind to Max is the example of Tony D. and his gang. Also known as "Blade," Tony D. and his gang confront Max and Kevin at the Fourth of July festivities. The gang pursues Max and Kevin to do them harm, and Max puts Kevin on his back in order to run away. This is how they became "Freak the Mighty." 
In the chapter entitled "The Damsel in Distress," Loretta Lee and Iggy are not very kind to Max. Loretta recognizes him as "Killer Kane's" kid. Loretta says, "He's some kinda retard, Ig. He don't even know how big and strong he is, I'll bet." 
In the chapter entitled "Killer Kane, Killer Kane, Had A Kid Who Got No Brain," when Max's teacher Mrs. Donelli asks him to stand and tell the students about his summer, kids in the class begin taunting, saying, "Forget it, Mrs. Donelli! His brain is in his tail!" They also shout, "Ask him to count! He can paw the ground!" and "Maxi Pad, Maxi Pad, ask him quick about his dad!"