How does Bryon feel about fights and beating people up in That Was Then, This is Now?

In the beginning of the book, Bryon is very nonchalant about beating people up; he likes fights, and thinks they are exciting, and nothing more than a fact of life. He says,

"...there were still gang fights around here and social-club rumbles, and things like Shepard's jumping M&M happened every day. I didn't mind it much, unless I was the one getting mugged. I liked fights."

Bryon begins to think about his attitude towards fighting, as well as other things, however, when M&M, whom he and Mark have just rescued from some thugs, becomes irate when Bryon and Mark consider jumping a another guy on the street just because he is black. M&M emotionally points out the paradox between

"rescu(ing) (M&M) from some guys who were going to beat (him) up because (he's) different...and now (Bryon and Mark are) going to beat up someone because he's different from (them)" (Chapter 1).

For now, Bryon just shrugs off M&M's abhorrence of senseless violence, excusing the boy because "M&M was only a kid, just turned thirteen," but as the story progresses, the truth of what M&M says begins to make sense to him. Bryon's views change as he matures and begins to think about his actions and the world around him, and therein lies the central conflict of the narrative - Bryon develops a moral conscience and begins to grow up, while Mark does not.