roman, as usual comfily slides over the fact that society was ´´self-policed´´ by having kgb ´´contact person(s)´´ in every collective. my dad worked in scientific institute - they had one known one, maybe 2 more (they were not sure) (scient. collective size about 100). my high-school estonian language/literature teacher that i revered, turned out to be one etc. local kgb bureaus worked with their contacts, agents, snitches. they themselves usually appeared only on more important cases, thus making it more impressive.
local KGB tried to even infiltrate punk movement, but after couple officers ended up in hospital, due to really heavy alcohol poisoning they kinda backed down
You are mixing information sources (who provide information post factum - useful for investigation, but too late to prevent damage) with people able to do active things to prevent or stop misconduct - police officers, operatives etc. Were your father's colleagues or your teacher able to arrest aggressive drunk man in public place? Check suspicions person papers on the street? React to break-in in progress?