I can understand that, but they also need to realise, sites like this is how they can get good exposure for their games as well.
I found literally every game i subscribe to on here, and when i first discovered AVN's i was playing everything free from here, but as money was available, i started subscribing to all the games i like (could afford to), so in essence yes, the site could possibly lose them (some/very little) income, but they also need to realise that most (not all) people who download games for free from places like this were never going to subscribe/pay for them anyway, or don;t have the money to, so essentially they lose barely anything from sites like these, they should focus more on the exposure they get for their games here and all the people who will subscribe by finding them here.