That's assuming that Apollo brings in enough revenue to cover the costs and they want to run a business.

I'm not a user of that App so excuse me if I am mistaken, if Apollo is currently free and without ads then the developer had a lot less to worry about then than now.

Additionally the outrage, as far as I am aware, has less to do with Reddit needing to make money rather it's way of going about making money is killing the user experience which kills the point of the website.