Should I interpret "direct compelling power" part as "complete convincing/constraining power"? does

Should I interpret "direct compelling power" part as "complete convincing/constraining power"? does "complex" refer to both "definitions" and "abstractions"?

If converts in far-off lands have in these days been shown to deteriorate when they become Christians, it is because the Christianity which they have embraced has lost all the direct compelling power which existed of old.

The Catacombs, also, it may be remarked, are a proof of the simplicity of early Christianity before it became barnacled over with all sorts of complex definitions and abstractions,.....


"The History of Spiritualism," by Sir Arthur Conan Doyle