As I understand it, both describe injustice increasing but in different ways and scopes. Broken Windows is an unstable system (a small deviation from the norm directly causes more and more issues) whereas the tipping theory they describe is a stable system that is inherently unfair (if a neighborhood is good, it'll increase more than bad neighborhoods). It's "spiraling out of control" versus "increasingly unjust". Broken Windows is about a direct criminological cause and effect: if there's a broken window, anything within eye sight is at risk. The problems they (and I) are thinking about are more structural, at a larger scale and much more indirect, e.g. nice streets increase property value which increases tax revenue which increases government spending to those streets. (Also, Broken Windows has been heavily scrutinized in case you didn't already know that.)