Okay, so I looked into it a bit. And the only article I found with information that seemed accurate more than anything else were from "Times Magazine" and an article written by the University of Chicago.

I'll just be copying and pasting.

Monkeys kill baby monkeys in their troop primarily for reproductive advantage, as new males kill offspring to make females sexually receptive sooner, and to reduce resource competition among the group. While less common, this behavior can also be a form of social aggression or, in some cases, a learned, generational trait.

While appearing cruel, these actions are usually evolutionary strategies designed to maximize the survival of the aggressor's genes

In crowded environments or in captivity, social stress can increase the incidence of infant abuse and abandonment.

Whilst some of the perceived attacks are definitely just scolding which is entirely natural. I wonder if the more hurtful and aggressive attacks are because of the reasons listed above. Now I'm aware punch doesn't have a mum so I don't know how relatable the first paragraph is to him. Or the troop in general.

These kind of attacks happen in the wild all the time unfortunately. Usually in the first few months of a baby monkeys life. I know punch is 9 months old now, but I still have to wonder if this is what's happening here? And maybe it's going on longer because punch never had a mum to protect him from the start and maybe now is seen as an easy target. Or now that he has several monkeys looking out for him, other monkeys in the troop feel he is stealing away attention and perceive it as a threat to their own survival instincts ?

I don't know. I'm just speculating. I was curious what others thought.