These people lose the one good thing their bad behavior had going for it: shame. They used to at least feel embarrassed about doing wrong. Now they praise what once made them blush. They actually boast about their vices. Once shame is gone, it can never come back — especially when you give disgraceful laziness a respectable name. This is why your school's praise of pleasure does so much damage. The honorable parts of your teaching go unnoticed, but everyone sees the degrading parts.
They lose, therefore, the one virtue which their evil life possessed, that of being ashamed of doing wrong: for they praise what they used to blush at, and boast of their vices. Thus modesty can never reassert itself, when shameful idleness is dignified with an honourable name. The reason why that praise which your school lavishes upon pleasure is so hurtful, is because the honourable part of its teaching passes unnoticed, but the degrading part is seen by all.