They were sticking to the text only. Fundamentals. Law.
Religion-as-tool for betterment can be powerful. That is the spiritual component.
Religion-as-law-without-spiritual component be extremely dangerous.
A hammer used to put a nail in the wall is the proper use for the tool.
A hammer used to murder somebody is not the proper use of the tool.
When religion is used solely for law purposes, there is no belief required by anybody.
It’s just the law that must be followed, like any secular law.
Without the wisdom in application, the texts are useless.
With the wisdom, the texts are a powerful support system.