The eternal religion is called Sanatam Dharma in sanskrit which has the name 'Vedic religion'. The modern name for the Vedic religion is 'Hinduism'.
The followers of the Sanatam Dharma, the Vedic religion or Hinduism are called the Hindus.
Most Indian Hindus (non-ISKCON devotees) are basically impure followers of the Vedic religion, and the hare krishnas are pure followers of the Vedic religion, thus pure Hindus.
The hare krishnas follow the Vedic scriptures like the Bhagavad-gita completely and properly. The Indian Hindus do not follow the Vedic scriptures properly or completely. Most Indian Hindus worship all sorts of beings as Gods. Millions worship Lord Shiva as God, millions worship Lord Bramha as God, millions worship Sai Baba as God, millions worship Swaminarayan as God, millions worship Kali as God, and millions worship Krishna as God.
Thus within the Indian Hindus, some are pure followers of the Vedic scriptures like the Bhagavad-gita (those who worship Krishna as God) but most are impure followrs of the Bhagavad-gita as they act against the injunctions of the Bhagavad-gita, as they worship demigods and Gurus as Gods.
What does the Bhagavad-gita say about who to worship?
"Whatever a man sacrifices to other gods, O son of Kunti, is really meant for me alone, but it is offered without true understanding. I am the only enjoyer and the only object of sacrifice. Those who do not recognize my true transcendental nature fall down." (Lord Krishna, Bhagavad-Gita 9.23)
"He who follows this imperishable path of devotional service and who completely engages himself with faith, making Me the supreme goal, is very, very dear to Me." (Lord Krishna, Bhagavad-Gita 12.20)
What does the Bhagavad-gita say about who not to worship?
"Men of small intelligence worship the demigods, and their fruits are limited and temporary. Those who worship the demigods go to the planets of the demigods, but My devotees ultimately reach My supreme planet." (Bhagavad-Gita 7.23)
It is clear from the Vedic scriptures that Lord Shiva, Lord Brahma, Lord Indra are demigods who should be respected but not worshipped as God. And those who worship Gurus (Sai Baba, Swaminarayan etc..) as Gods are most degraded followers of the Vedic religion.
Those who worship Lord Krishna as God are the purest followers of the Vedic religion (Hinduism). The hare krishnas represent the purest Hindus. The hare krishna movement is based on krishna consciousness, thus the name, the international society for krishna consciousness (ISKCON).
Srila Prabhupada clearly wanted his followers to worship only Lord Krishna and not demogods or Gurus as God, that's why he set-up the International society for krishna consciousness (ISKCON). In the temples he built (to my knowledge), there were no dieties of demigods (Shiva, Ganesh, Bramha) on the altar, only Krishna and his incarnations. The reason being we should focus on worshipping Lord Krishna only, only Lord Krishna. If there are many dieties on the altar, then the focus on Lord Krishna becomes diluted and thus we gradualy diverge from krishna consciousness. Thus diverge from the principles of Srila Prabhupada's ISKCON.
Thus although having many dieties on the altar (Lord Krishna and demigods) may be looked upon as diluting krishna consciousness. This can also work for the benefit of ISKCON, by attracting the average Indian Hindu who is currently in ignorance of the Vedic scriptures as he worships demigods or Gurus as God. The aim of Srila Prabgupada's movement is to help the fallen souls which includes helping most Indian Hindus come out of ignorance by making them krishna concious.
