Final answer:
The claim that 'it is a pity that pleasure is a sin and sin is pleasurable' is not explicitly stated in stanza 133 of Don Juan. Literature and philosophy often explore the complex relationship between pleasure and sin, but this particular claim does not directly match the content of the provided stanza.
Step-by-step explanation:
The student's question asks whether in stanza 133, of Don Juan the poet claims that it is a pity that pleasure is a sin and sin is pleasurable. Despite the complex views on pleasure and sin found in literature, this specific claim does not appear verbatim in stanza 133 of Byron's Don Juan. You have provided several quotations exploring the relationship between sin, suffering, and pleasure from different texts and philosophical perspectives, but none affirm the exact sentiment in stanza 133 of Don Juan.
For example, the character of Glaucon in Plato's work would prefer truth over false pleasure, Mill's philosophy suggests that intellectual dissatisfaction is preferable to simple animalistic contentment, and Buddhist teachings on suffering indicate that craving and attachment to pleasure lead to suffering.