Vigilante Loadout

you mean minecraft villagers beheading zogbots and reporters in minecraft?

So to reduce crime effectively we'd have to form our own vigilante cartel?

Torture and the general infliction of unnecessary pain, believe it or not, tends to make people more determined to kill you rather than the other way around

Tell that to Vlad the Impaler.

Torture and pain are necessary to instill fear upon your enemy.

Your enemy doesn't fear being shot.
It fears being impaled on a big long stake and dies slowly in agony.

Nice idea. Alternatively, taser and burn, if you can afford / need more publicity.

What are the most practical techniques to disable cameras in minecraft without being discovered by zombies?

Depends how you do it. Up to a certain point I can see your argument there, but at some point (which may well vary from person to person and group to group) you hit psychological critical mass and the reaction switches from anger to fear.

In theory one man could keep a relatively large area protected with only the support he can arrange for himself. If you turn it into a cartel then you run into all kinds of risks regarding the guys calling the shots. A network might not be a bad idea, as that could help individuals and if one man goes rogue then he's still just one man. A cartel, even just a regional one, has the potential to cause a lot more harm than good and is much harder to correct if it goes off course (remember that's basically what happened with most far east organised crime groups).

I've heard the retina some cameras can be burned out with a strong laser. I tried it on an old cellphone (not the same as a security camera obviously) and it took a good while for the retina to burn at point blank, so perhaps that would be impractical for aiming at a high-ish up security camera

Bows and such are a bit larpy. Its not that it wouldn’t work its that they are bulky and thus not readily concealable.
Under what circumstances would they be used? Killing random niggers walking down the street? Shooting through a window from a roof top across the street? Not impossible but a little impractical for standard mo outside of specific situations.

Like any hunting you must first determine what the prey is and what its habits are: Public? Sociable with friends? Reclusive? Where are they most vulnerable? What patterns can you exploit?
You need to exploit the weakness most likely to give success and build your strategy and any weapon use around that.
Eg:
Minecraft taxi drivers.
Good choice because they work solo and odd hours.
They can also be called out to a location more or less of your choosing at your convenience.
Decide the kill zone.
Call out taxi.
Get in cab behind drivers seat and before car moves off garotte from behind with a paracord and dowel garotte?

Other examples: i believe Carbon Monoxide cylinders are sometimes sold for use in minecraft for welding and would make it theoretically possible to gas a single room or perhaps more if the gas is administered via tube into an air vent or open widow say, at night when occupants are sleeping?

While were on the subject of gas, what about a home made fuel air bomb using compresses air running through a cannister of petrol and out through a nozzle to create an aerosol effect and ignited? If placed in air conditioning vents and ignited by timer after a delay it would perhaps result in enough coverage to destroy the whole structure in minecraft?

If sufficiently virulent poison can be made in minecraft then what about a simple BB gun with pellets coated with it? Quiet, easily obtained and concealed but slow acting or so i assume?

What about learning the fabled death touch pressure points from youtube and testing them in minecraft?

Surely the goal of this hypothetical vigilante project is to instil sufficient fear in the criminal population that they no longer want to make life harder for the community you're protecting?

Humans are social animals. As such we've evolved some very strong social instincts, not the least of which being empathy. The criminals who engage in violent crime have either overcome this social instinct, or don't have it in the first place. People like this are known as psychopaths and sociopaths.
Social instincts aren't the only thing that keep people from committing violent crime; it's actually a dumb idea from a risk/reward point of view a lot of the time. Yet these people, who are obviously interested in their own well-being, still engage in this high-risk behavior. Why? Because one of the symptoms of psychopathy and sociopathy is a relative inability to mentally process consequences. They just have difficulty thinking about the bad stuff that could happen to them. This means that the severity of punishment is especially unlikely to inform their decisions, because as a rule, they have a diminished ability to understand that they are putting themselves at risk. They just can't think about it.
Add to this the fact that psychologists have found repeatedly that punishment-based behavioral modification techniques are comparatively ineffective on even intelligent, socially healthy and aware individuals, and the only sensible conclusion is that they Batman method ("I'll just scare the criminals into not doing crime") is ill-conceived. Hell, it doesn't even work in Batman's fictional universe; the guy is cracking skulls every night and the city is still constantly overrun by violent weirdos.
So what is effective if severity of punishment isn't? The answer is: the likelihood of getting caught. Even a comparatively minor punishment is more effective at reducing recidivism IF it's more likely to be administered. You want to bring down violent crime? Don't waste your time torturing Jaykwon all week; you'll be tied up with that while Tyrone and Jamal are free to pull their shit.
The most effective policy would obviously be universal armament: as proportion of armed victims approaches 100%, the likelihood of successfully robbing them approaches 0%. Second best would be systematically collecting conclusive incriminating evidence and sharing them with authorities. Obviously this would be more effective if they aren't tied up with nonviolent crime, so leave the druggies alone unless they're attacking people or stealing shit.

TLDR: Your Batman fantasies don't even work for Batman. You are not a bad enough ass to scare the Crips away.

Oh yeah -
Plus, nobody will see it as you going after criminals; they'll see you as a serial killer sadistically lynching minorities. They won't participate in your Punisher LARP. They'll do what they always do: call you a racist and unite against you. They'll probably even riot, and now you've shot yourself in the foot.