Language evolves constantly but even in my youth I don't recall 'You bugger, you ate my favourite chocolate!' to mean that an anal rapist or participant in anal sex ate the complainant's preferred piece of confection.
"Why not call it "Getting the fuckers to behave"? It amounts to much the same thing!"
Why not indeed? In years to come, as language evolves, someone might.
Bugger/buggers is such a common word that I doubt if anyone using it is thinking of anal sex. It's just jokey. It's on a par with 'little sods'. No-one imagines that it refers to actual sodomy. Sometimes one can be a tad too literal in reacting to light-hearted banter.
Great book though. I also enjoyed "Getting the Buggers to Think" but that was years ago. I imagine Ofsted have changed their mind about how children need to think (I.e. to show that they are thinking) in the meanwhile.