That's exactly because the only necessarily important thing is "does it work?" So the rest is open to interpretation and susceptible to religious behavior.
"does it work?" is also open to interpretation and susceptible to religious behavior.
There is a paper [0] which documents an interesting disagreement about a project: The developers considered it a huge success but management considers it a complete disaster. Very different interpretation. Does it work?
As an example for religious behavior we could look at Powerpoint. An application which is used with practically religious fervor. However, the application is mostly misused so badly that the goal of supporting the transfer of knowledge or persuading people is not achieved. Does it work?
Without agreement about the goal/requirements, you can not determine if the resulting software works. In my experience, precise goals/requirements are often missing, so a simple question like "does it work?" is also open to interpretation.
[0] Software Developer Perceptions about Software Project Failure: A Case Study by Kurt R Linberg, 1999
