It's because all those big corporations outsource their customer service to India and surrounding countries, and whenever we get a call from those outsourced agent, they're always unable to do anything because they're not given access to the big corps network. So specifying 'Indian' most likely meant that - the typical outsourced customer service - instead of being a specific rant about the nationality. It could be any other nationality if the Call Centre of this World were held somewhere else.

Now I'm not saying this is appropriate or not, I'm just explaining the reference.