The Buddha spent a lot of his career trashing the Indian Brahmins not only for usurping the rightful caste order (as the warrior class originally had supremacy over the Brahmin class), but he ridiculed the elitism, hedonism, and aristocratic attitude that was opposed to the original purpose of the Brahmins. Claiming to be the Savior of mankind (bringing forth the true Dharma, allowing people to break free from Samsara), he taught a doctrine, while heretical to the Brahmins, which made it clear that all human beings (and all sentient beings) had inherent worth regardless of your race, sex, age, class, and wealth, and we were all one. He taught all human beings were capable of enlightenment and doing moral good.

How do the Vedics in India respond to the Buddha?

They think he was a great dude. They are thankful that he was able to teach the Dharma, Enlightenment, and a form of Moksha to the tribal and uncivilized East Asians. Many Indians can't get over the fact that half the world honors and worships a man from their continent, and some think he was an incarnation of their god Vishnu.