I will pass this favor on that I got from a movie thread here about a year ago.
Although not a vigilante film, if you like 70s films you owe it to yourself to watch cult film The Warriors (1979).
If nothing else a great use of NYC as a backdrop. Yeah a bit cheesy, but imagine watching it in 1979.
Saw it in the early 80s but it was very clear that the city was still just a jungle.
When I visited NYC as an adult in 1985, it looked pretty much the same.
When I returned in 2000 or so, it was like a completely different city.
Kids and families walking around in Times Square?
Not in the early 80s.
And to your point, one of my friends said that when Death Wish was shown to 1974 audiences, that people were clapping and cheering when "the punks" got shot.
IIRC, in the novel, Paul Kersey is a milquetoast liberal who wouldn't hurt a fly.
That's why when he starts fighting back, he gets physically sick.
It turns his whole world-view upside down.