Practice precedes perfection.
Yes, there is a terrible moral in 'Dorian Gray' - a moral which the prurient will not be able to find in it, but it will be revealed to all whose minds are healthy. Is this an artistic error? I fear it is. It is the only error in the book.
There were sins whose fascination was more in the memory than in the doing of them, strange triumphs that gratified the pride more than the passions, and gave to the intellect a quickened sense of joy, greater than any joy they brought, or could ever bring, to the senses. But this was not one of them.