Re Hinduism:
As far as Vedic religion is concerned, it is not for the Hindus; it is for all living entities. That is the first thing to be understood. Vedic religion is called sanatana-dharma, "the eternal occupation of the living entity." The living entity is sanatana [eternal]. God is sanatana, and there is sanatana-dharma. sanatana-dharma is meant for all living entities, not just the so- called Hindus. Hinduism, this ism', that ism'"these are all misconceptions. Historically, sanatana-dharma was followed regularly in India, and Indians were called Hindus' by the Muslims. The Muslims saw that the Indians lived on the other side of the River Sind, and the Muslims pronounces Sind as Hind. Therefore they called India Hindustan' and the people who lived there Hindus'. But the word Hindu has no reference in the Vedic literature, nor does so-called Hindu dharma. Now that sanatana-dharma or Vedic dharma, is being distorted, not being obeyed, not being carried our properly, it has come to be known as Hinduism. But that is a freak understanding. We have to study sanatana-dharma; then we'll understand what Vedic religion is. [To a devotee] Read from the Eleventh Chapter of Bhagavad-gita, eighteenth verse.
Re demigods and Deity worship
"Men in this world desire success in fruitive activities, and therefore they worship the demigods. Quickly, of course, men get results from fruitive work in this world." (Bhagavad Gita 4.12)
"Endowed with such a faith, he endeavors to worship a particular demigod and obtains his desires. But in actuality these benefits are bestowed by Me alone." (Bhagavad Gita 7:22.)
Demigods and demigoddesses are often mentioned in Vedic literature as the extraordinarily powerful controllers of the material world. The Supreme Being, Krishna, doesn't directly manage the affairs of the universe; He appoints other qualified living entities"His devotees"to act on His behalf.
For example, Krishna entrusts Brahma with creating the universe and Shiva with annihilating it. Krishna's expansion, Vishnu, takes charge of its maintenance, but in a "hands off" style; He posts other demigods to look after the various aspects of universal management.
The Vedas sometimes encourage worship of demigods as a reward system to encourage pious activity. People desiring temporary, material benedictions worship demigods, with the goal of with goal of enjoying worldly, heavenly pleasures in this life and the next.
In the Bhagavad-Gita, Krishna discourages such materialistic worship, reminding us that such benedictions, like the demigods themselves, are limited and temporary. He recommends that anyone seeking true, lasting happiness should worship Him instead, since He's the ultimate source of all benedictions and demigods anyway.
Lord Krishna is non different from His form. When we worship His form, we are worshipping Him. He says in Srimad Bhagavatam 6.16.51
[Lord Sankarsana to King Citraketu] All living entities, moving and nonmoving, are My expansions and are separate from Me. I am the Supersoul of all living beings, which exist because I manifest them. I am the form of the transcendental vibrations like omkara and Hare Krsna Hare Rama, and I am the Supreme Absolute Truth. These two forms of Mine'namely, the transcendental sound and the eternally blissful spiritual form of the Deity'are My eternal forms; they are not material.
Re cow protection
namo brahmanya-devaya
go-brahmana-hitaya ca
jagad-dhitaya krsnaya
govindaya namo namah
My Lord, you are the well-wisher of the cows and the brahmanas, and You are the well-wisher of the entire human society and the of the entire world.
Purport: In this prayer we see that special mention is made of the cows, indicating that special protection must always be given to the cows who are very dear to the Supreme Lord. The Lord is very fond of cows and we are encouraged to give reverence and love to the cow. For the cowherd men and the cows, Krsna is the supreme friend. Therefore, He is worshiped by the prayer " namo brahmanya-devaya go brahmana -hitaya ca". His pastimes in Gokula, are always favorable to the brahmanas and the cows, His first business is to give all protection to the cows and the brahmanas. In fact ,comfort for the brahmanas are secondary, and comfort for the cows are His first concern ( Srimad Bhagavatam 10.8.16 Purport)
Re caste:
catur-varnyam maya srstam guna-karma-vibhagasah [Bg. 4.13]. The Lord says that "The four divisions of social order -- namely the brahmanas, the ksatriyas, the vaisyas, sudras -- these divisions were created by Me," and guna-karma-vibhagasah, "not by birthright but by identification of qualities and actual work." In the similar way, in the Srimad-Bhagavatam also, it is stated that yasya hi yad varnabhivyanjakam, laksanam syat. Yasya hi yad laksanam syad varnabhivyanjakam, tat tenaiva vinirdiset [SB 7.11.35]. The whole Vedic system is to pick up qualitative persons. There is no such thing as birthright qualification.
Re Bhagavad Gita
http://www.gitadaily.com/what-is-the-bhagavad-gita-as-it-is/
No offences meant to anyone. Just sharing what I've read and am trying to imbibe.