I have used the term to refer to dd's junior school but I hope that I have only ever done so in a context that made it clear that by "school" I was referring to the school management and their ethos, not to individual teachers and children
in the same way as when the school (= the management) talks about "our ethos" they are actually referring to the ethos of the management, not of every single child in Yr 5.
in the same way as I might describe a company as shit if they pollute the environment and circumvent employment law- and would still hope to have it understood that I am not referring to every single employee including the cleaners and the man who services the computers
if by "the school" you understand the same thing as "the school" understands in their official correspondence, i.e. the people in charge, then I shall, with all due respect continue to refer to dd's junior school as a shit school
but I shall also point out that the children and parents were lovely and that the teachers were well meaning though not always with the courage to stand up against the management
(though when it comes to openly flouting the Disability Discrimination Act, I would say that any teacher who lacks the courage to speak out is, actually, a bit shit- as is any citizen who stands by and sees a vulnerable person maltreated)
and when I speak of dd's current school as a lovely school, I am referring to the same thing- the ethos, the management, the people who decide the ethos of the school- not every single teenager in Yr 10