(This is a philosophical question. Just exploring ideas)
Increasing number of people have nothing to lose. Rioting is pointless and dumb and can land you in jail. People publicly writing "bad stuff" on social media are risking jail-time or at least having their lives destroyed.
Why is nobody killing the rapists and murderers? Why is there no secret organization cleaning up the streets? Why are politicians and "public servants" allowed to feel safe?
I think this is a historical anomaly.
Somebody else mentioned Christianity and Islam. Religion has nothing to do with it. It's Latin America where 'autodefensas' are the most prevalent and well organized, not Muslim countries.
Furthermore, crime isn't as pervasive in most White neighbourhoods as it is in Latin American countries. It took years to decades of living under fear of cartels before autodefensas really got going, and decades of living under crime before some Brazilians started to develop similar vigilante behaviours (e.g. ramming their cars into the getaway bikes of robbers). Before that, the Brazilian attitude was just one of pure apathy, and largely still is.
I've seen videos of Brazilians being shot dead: many spectators don't even flee from the sound of gunshots like White people would. Most White people would scream and run without conscious thought. My suspicion is that they're so well adapted to a crime-ridden environment that crime is no longer shocking: they neither scream nor run, and barely even look in the general direction. Rather, they simply continue going about their day.
Some Brazilians also have an attitude that is like this: 'Most crime only happens to people who are involved in drugs and gang life. Since I am not involved in drugs and gang life, I do not need to worry about it, it will not affect me.' That is, of course, simply another rationalization for their adaptation. Plenty of students and other people unlikely to be involved with drugs and gang life also end up being shot dead.
Of course, adaptation can only go so far. For some, crime became so pervasive that it led to anger and fear. I think that contributed to Bolsonaro's election victory, and vigilante activity increased at that time. Come to think of it, I think it has probably decreased again, probably because these people felt emboldened by Bolsonaro, whereas the return of Lula to the presidency has removed those feelings.
The other main point is that vigilantism is deeply anti-Western: since the Enlightenment, Whites have liked to govern themselves by the 'rule of law'. Taking the law into your own hands has been seen as wrong for centuries.
These factors and others all lead to the same conclusion. People are too engrossed in entertainment and work to really be aware of the crime around them. Even if they are not, people are too individualized to really care about it until it affects them or those closest to them. Even if it did affect them or those closest to them, the prevailing political culture and ideologies are against vigilantism, and usually strongly prefer to relegate all such matters to a standing police force. Even if it wasn't, crime isn't perceived as pervasive enough to justify adapting that political culture. Even if crime got out of hand such that some started to feel that way, most people would simply pathologically rationalize why they should hold on to their unjustifiable apathy.
You have to go through or somehow around all of these hoops and others before vigilantism could become normalized among Whites. It is thus no surprise that there is not a single White country in which all of these hoops have been passed such that vigilantism is actually normalized. I don't recall once a seeing a video of vigilante activity from outside of Africa and Latin America.
Furthermore, African vigilante activity is generally spontaneous and has no organization: a crowd simply amass and stone or burn a suspected criminal to death. Their pathway to vigilantism is probably substantially different from any way Whites could arrive at it: e.g. anger plus low impulse control happening enough to lead to normalization of vigilante actions. Whites are too high impulse control to behave like African crowds, preventing enough spontaneous vigilante actions happening, preventing normalization of said actions.