You don't seem to know much this at all.
The Ofsted visits may not be ideal as a means of assessment of a school, but they are not solely about about the behaviour of kids or class discipline, though that is clearly part of the indicators considered.
It is also about robust processes and systems in place, methods of review of these, good management and leadership from the top.
The reason why such inspections were felt necessary in the first place was that Heads and senior teachers were, in general. useless at managing people and processes, though many were damn good teachers, which is how they got promoted in the first place.
I would put it to you that both Government and Ofsted do understand about the behaviour of many kids being a key issue. But that's an indictment of morals and society in general.