They feel like they get shorted because many of those users don't contribute to ad revenue from 3rd party apps but instead of improving their app to lure users in they instead tell those users to fuck off.
A user is a user, even if they don't contribute directly to ad revenue they contribute content to make the site more alluring for those who will contribute to ad revenue. As well they help spread the word about reddit to those who don't use it regularly yet by sharing that content outside of reddit.
They were pretty short sighted by doing what they did.