This has been my experience as well. I, too, have met and talked to thousands of people from every possible background on seven different continents of this world. From the poorest people on Earth to some of the richest.
I've seen the same thing. About 5% are nasty and about 1% are truly bad people who commit horrible crimes.
Saying this from my personal experience [ workspace related not familial ] : What happens is that some of these bad people have charisma, can make you follow them, for their ulterior motives. So if you get trapped in that circle, because you tolerated for so long, you probably did not get to experience the 5% bad, but maybe 20% bad over your lifetime. So my lesson there is ... walk. You recognize a problem, you walk, rather than try to fix it. Of course you should give a chance, but that is it - just one chance and then none.
Makes me wonder if the distribution is independent of other personality and socioeconomic factors.
Much earlier in life I helped recruit for a cult (much has changed since then). 3% - 5% seems on the high side for people who "just suck" -- perhaps by an order of magnitude. But perhaps the "just sucks" is context dependent. I found early on the FORD bulletpoints makes it pretty simple to start smalltalk (Family, Occupation, Recreation, Dreams/Desires).
IDK about "horrible" but https://www.sentencingproject.org/research/ puts it at 1.5 million peak. Thats not quite 1 percent of the US population but its also not that far off. And we can quibble about US sentencing rules but the BoP has a count[1] of felony categories and drugs make up less than half, and its even less in state prisons.
The reason the estimate feels high is likely that the HN crowd is progressively separated from less stable elements of society. The bullies picking on kids at recess don't generally make it onto the gifted / accelerated track, or your 4 year degree granting university. You're going to encounter fewer of them at upmarket shopping centers and corporate offices, if for no other reason, 1.5 million people are in prison.
I've seen the same thing. About 5% are nasty and about 1% are truly bad people who commit horrible crimes.