Human beings cannot bear much reality. That is the basic point that Plato was making in The Republic. Thus corruption, which is endemic in human society, is often covered up by charm; this makes the corruption bearable. But nevertheless, as Plato pointed out, it doesn't get at the real root of the problem.
The fault is really two-fold. Lack of real charm; and a surfeit of corruption.
Wilde, by merely focusing on the aspect of charm, was ignoring the corruption endemic to human society; presumably, he thought this unfixable - but I do wonder how he would have considered this after his experience in Reading Gaol.