It is at least historically important to note that at least Nietzsche and Stirner were reacting to Protestantism as expressed in "modern" Germany.

I'm not trying to make a "No True Christian" argument but rather just want to assert that reform does happen both for good and ill. Luther's original reform, in part, was to point out that political concerns within the church were overriding the spiritual concerns of the laity. He wanted to refocus faith on a personal relationship with God. One major criticism of that refocus is that it caused individuals to become over-focused on the self instead of God (as embodied in the institution of the church).

In both cases you could argue that the principle problem is when the focus of faith is something in the world (either the church or the individual). So I think it is perhaps too far to say that "we have always been worshipping ourselves" when the criticisms within and without the church are pointing that out as the problem that triggers the reform.

That is, both Luther and Stirner can be correct in their criticism of religious institutions. There is more than one way to get it wrong.