There's also a difference between what a religion teaches and what an individual of that religion believes.
By all means, which is why I mentioned my experience in rural Italy. Living now in Utah I can also cite differences between what the Mormons teach officially and what some of its members believe and attribute to the faith. And as I wrote above, putting
Malleus malificarum on the Index didn't prevent people from using it with the belief that it gave them divine justification.
Further, there are also historical shifts in doctrine within a religion. Again, living in Utah (although less important now with the advent of the Internet) lets me look at some of the very strange things Mormon leaders taught and believed in the 1800s. Although they aren't taught today, you can't just walk away from them. Professors of religion make bold claims, not the least of which is some form of communion with an almighty superbeing. If some of those claimed communions end up in retrospect looking quite provincial and anachronistic, this casts doubt on the claims.
A discussion of god's purpose can't escape that there is ever only an attribution of purpose. All statements of god's purpose are third-party claims. It therefore cannot escape the followup question, "How do you know?" Presenting a sanitized version of some religion's progressive groping for answers to those questions does disservice to the claim. While it is in an organized religion's best self-serving interest to portray it's formulation of god's purpose as reliable, resolute, and never-changing, the reality is always far different.
And that brings us back to your original statement, and my observation some posts above that we are not diligent if we simply limit candidate attributions of god's purpose to the most recent sterile, abridged decretals of the titular churches. There is nothing magical or necessary about the centralized bureaucracies of these that limit consideration of belief. There are a vast number of people who identify loosely under one banner or another, but who fly their own private flags regarding god's purpose. Pointing out that they don't adhere to some prepackaged version of Abrahamic worship doesn't somehow mean we don't consider their claims.