By His Divine Grace A. C. Bhaktivedānta Swami Prabhupāda
In Bhagavad-gita (7.20) it is said that persons who worship demigods have lost their intelligence: kāmais tais tair hrta jnānāh. They are much attracted to sense gratification, and therefore they worship the demigods. It is, of course, recommended in the Vedic scriptures that if one wants money, health or education, then he should worship the various demigods. A materialistic person has manifold demands, and thus there are manifold demigods to satisfy his senses.
The grhamedhīs, who want to continue a prosperous materialistic way of life, generally worship the demigods or the forefathers by offering pinda, or respectful oblations. Such persons are bereft of Krishna consciousness and are not interested in devotional service to the Lord. This kind of so-called pious and religious man is the result of impersonalism. The impersonalists maintain that the Supreme Absolute Truth has no form and that one can imagine any form he likes for his benefit and worship in that way. Therefore the grhamedhīs or materialistic men say that they can worship any form of a demigod as worship of the Supreme Lord. Especially amongst the Hindus, those who are meat-eaters prefer to worship goddess Kālī because it is prescribed that one can sacrifice a goat before that goddess.
They maintain that whether one worships the goddess Kālī or the Supreme Personality of Godhead Vishnu or any demigod, the destination is the same. This is first-class rascaldom, and such people are misled. But they prefer this philosophy. Bhagavad-gita does not accept such rascaldom, and it is clearly stated that such methods are meant for persons who have lost their intelligence. The same judgment is confirmed here, and the word kāma-mūdha, meaning one who has lost his sense or is infatuated by the lust of attraction for sense gratification, is used. Kāma-mūdhas are bereft of Krishna consciousness and devotional service and are infatuated by a strong desire for sense gratification. The worshipers of demigods are condemned both in Bhagavad-gita and in Srimad-Bhagavatam.
[Bhaktivedanta Purport to the SB 3.32.2]