taṁ sannibhartsya kupitaḥ
The word śukra means “semen.” The sons of Śukrācārya were brāhmaṇas by birthright, but an actual brāhmaṇa is one who possesses the brahminical qualities. The brāhmaṇas Ṣaṇḍa and Amarka, being seminal sons of Śukrācārya, did not actually possess real brahminical qualifications, for they engaged as servants of Hiraṇyakaśipu. An actual brāhmaṇa is very much satisfied to see anyone, not to speak of his disciple, become a devotee of Lord Kṛṣṇa. Such brāhmaṇas are meant to satisfy the supreme master. A brāhmaṇa is strictly prohibited from becoming a servant of anyone else, for that is the business of dogs and śūdras. A dog must satisfy his master, but a brāhmaṇa does not have to satisfy anyone; he is simply meant to satisfy Kṛṣṇa (ānukūlyena kṛṣṇānuśīlanam). That is the real qualification of a brāhmaṇa. Because Ṣaṇḍa and Amarka were seminal brāhmaṇas and had become servants of such a master as Hiraṇyakaśipu, they unnecessarily wanted to chastise Prahlāda Mahārāja.