I think it is a bug. I think they relied too heavily on automation and scraping to get a list of all the restaurants, menus and prices. From the original article:
> My first thought: I wondered if Doordash is artificially lowering prices for customer acquisition purposes.
> My second thought: I knew Doordash scraped restaurant websites. After we discussed it more, it was clear that the way his menu was set up on his website, Doordash had mistakenly taken the price for a plain cheese pizza and applied it to a 'specialty' pizza with a bunch of toppings.
So I don't think its a feature.
> what possible moral or legal right does Doordash have to an operating profit when it deliberately operates at a loss?
It doesn't have an operating profit whether you exploit the bug or not. Doesn't mean its okay to steal from them. Even if they do deliberately lose money (e.g. first Uber ride free up to $10), exploiting it is unethical (e.g. tricking Uber into thinking you're on a new phone).
The rest of your argument is again, why you don't like Doordash or why Doordash is unethical. I won't address this point because I think its unethical to steal from an unethical company so their ethics is irrelevant.
If I think Walmart is unethical, is it okay shoplift from their stores?