what is the irony of education in the chapter Browning Version?

As Taplow says the teachers were all sadists, they got pleaure out of inflicting pain on students. He doesn't mention names but most masters thoughtthat the boys didn't understand a thing. Frank was appalled at hearing this because it did not reflect well upon the education system. Mr Crocker-Harris was an exception because he seemed to hate people who liked him, in fact he did not care about what impression he made on the students and just carried on with his work.