Because the blasphemy was cast against Sri Caitanya Mahaprabhu Himself, He did not feel sorry, and therefore He was smiling. This is ideal Vaisnava behavior. One should not become angry upon hearing criticism of himself, but if other Vaisnavas are criticized one must be prepared to act as previously suggested. Sri Caitanya Mahaprabhu was very compassionate for His pure devotees Tapana Misra and Candrasekhara; therefore by His grace this brahmana immediately came to Him. By His omnipotency the Lord created this situation for the happiness of His devotees.