You don't have to be "tech able". There are many assets that follow the "industry enabled" (loading and unloading) rules and work as intended.
Many of the ones that don't are older assets, created before "industry enabled" features were added to Trainz. They are kept on the system for a variety of reasons including being in "common use". Not everyone who uses Trainz wants cars loading and unloading at stations, industries, etc. Other newer assets were created without the "industry enabled" features, sometimes because their creator was not interested in adding the feature (it can be a lot of extra work with meshes, textures, scripts, etc).