They wanted to switch over to a subscription model. I assume many people like me who used to use infinity just bailed.
Edit: I actually dug up the source for this. It still worked for non subscribers until now. Apparently that will stop on august 30th. The headline is misleading. Starting in September it will be the aforementioned subscription model.
So if someone really wants to use an app for Reddit... Why not just use RedReader? That one has an exception due to havingb better accessibility support, and seems to do everything that any other app does.