Why is this rated so low?

Tumbleweed

Its a great action movie, some of Enzo's best action scenes are in this imo

Well, the film makes a lot of valid and intelligent points on the rise of fascism; a contentious point for most Italian's of the period given the rise of acceptable right wing politics during the 1970s and early 80s, during which the country was marked by terrorist attacks and escalating violence between the public and police. It's also largely about the exploitation of the working classes, where big business becomes the new totalitarianism.

The criticisms you make about things like plausibility, lack of character development and adequate performances you could just as easily make about any George A. Romero film, early Cronenberg or The Texas Chainsaw Massacre, all of which are flawed by their lack of budget, technical experience and a general nonsensical approach to plotting. But people look beyond those inconsistencies to see the themes and the subtext; they look at what the films are "about" and enjoying them on a level of pure sensation. This film is no different.

Escape from the Bronx might suffer from its exploitation roots, but it says more about fascism, industry and class-structure than glossy product like The Hunger Games or The Dark Knight Rises.