Can someone with more knowledge chime in here? From my western POV the step from "veg only delivery crew" to "caste based delivery crew" seems huge. The article makes it out like it's the logical next step. Seems a bit odd to me.
Now Zomato basically crafted this policy for God knows what reasons. Nobody gives a shit on how their food reaches them, as long as it reaches fresh and intact. No one except the same aforementioned group of bigots. There are some members of the upper caste community which tend to be very fanatical about their food preferences and seek to impose vegetarianism by proxy, including by demanding their food only be delivered by vegetarians. There already are restaurants which are staffed by upper caste members only, and this policy would be an extension of it.
I don't know what's Zomato's motivation behind it, except for a.) fanning a flame onto a non-issue to get a leg-up against the competition (it's an election year and some folks are going to be stoked about these kinds of policies), b.) currying favor with the upper caste majority, c.) currying favor with the current ruling party which likes these types of policies (fwiw the same party banned Halal meat in one state which they govern) d.) the CEO is just displaying his inner bigotry, e.) other not specified.
A Pure-veg mode is actually a good policy that helps the customer - ironically, I know a lot of Muslims who use such filters to stick to veg when travelling in places without Halal food. But having a Pure Veg Fleet is a purely bigoted policy that reeks of some kind of "vegetarian apartheid".
This reflects in other ways. For example, it's well known that in many cities, only certain castes are allowed to rent or buy apartments within certain housing societies and colonies, the excuse used being vegetarianism (and that non-veg cooking stinks, etc.). Many of my friends who are non-vegetarians have to stick to vegetarian food at home, and only eat non-vegetarian on the occasional outing.