Because the question put to him was not really about his own belief. It was about whether anyone at all could be compelled to change faith — and he had already answered that by agreeing to stand with the Kashmiri Pandits.
Why he did not convert. Notice the sequence in the chapter. He was not arrested first and asked to convert afterwards; he “decided to stand with them and court martyrdom”, and was then arrested. He had gone into the situation knowing what it would demand. If he had converted under torture, the demand made of the Pandits would have been shown to work — the very principle he had come to defend would have been broken by the man defending it. A refusal that gives way under pressure proves the opposite of what it set out to prove.
Why he thought it would make a difference. Three reasons, all visible in the chapter:
- He was not the one under threat. He had no personal quarrel to settle; he was defending other people's freedom of worship. That made the case impossible to dismiss as self-interest.
- It was public. A private death changes nothing. A public beheading in Chandni Chowk, of a man everyone knew had come on someone else's behalf, made the demand visible to the whole capital — and it was the executioners who had to explain themselves, not him.
- It matched what he taught. The Guru Granth Sahib, which he himself contributed hymns to, says: “Truth is high but higher still is truthful living.” A teacher who says that and then yields has refuted himself.