Slam Dunk's Mitsui: how much can a redemption arc forgive?

Now that I'm an adult, rereading it with a clear head, there's something I think about.
The lovable, deeply troublesome Hisashi Mitsui—the "Flaming Man"—went on a seemingly irreversible rampage right from his first appearance.
"I'll wreck it all."
His seemingly irreversible rampage:
He had a cigarette pressed into a basketball.
He spat.
He hit my Hanamichi with a mop. (A serious offense.)
He hit Glasses.
He kicked a basketball.
"Get out of the way!!"
What I think when I reread it is...
After going that far...
How did he manage to come back?
Hisashi Mitsui, in middle school:
"As long as this superstar Hisashi Mitsui is here, we're definitely going to win!"
I understand he was a former MVP whose ability everyone recognized...
"If you give up, that's where the game ends..."
He dreamed of winning the national championship more than anyone.
I do feel sorry for the setback caused by his injury...
"Coach Anzai!"
"You're late... Mitsui... After all this time."
"I want to play basketball..."
But you went too far!!

"About the past incident that left the heroine emotionally scarred..."
"She used to be a bully, right?"
"That's right."
"And the reason she was troubled was guilt over having driven someone to suicide..."
"That's one seriously messed-up heroine!!"
"But she properly repented for it in the story!!"
"No, no, that's not something you can settle just by repenting!"
"And then she acts like 'I'll live for that girl who died, too' makes it okay. I found that seriously frightening."
"This thing sells!!"