The frustrating thing, that was not brought up in the thread before they had a hissy fit and locked it down, is that the stated REASON you have to own the sources you use, is so you can provide those sources to the GM, which can be done on an electronic device, while at the same time, the REASON you have to have a paper copy of your character sheet is so you don't have to let the GM use your electronic device...
It actually was brought up, they just refused to address it because, as you say, they were mid-hissy-fit. :/