Most bicycle fasteners seem to be pretty well over-spec'ed, such that overtorqueing is not going to damage parts (except aluminum, titanium, and other weight weenie parts).
Most bike fasteners are screwed in and left until they need to be removed, often years or decades later.
When fasteners that have been left on for years are unscrewed, it takes a LOT of torque to remove them if they weren't greased during assembly. (That may be why they were over-spec'ed in the first place.)
So it's usually safe, and often beneficial, to grease steel-on-steel bolts before assembly. It's always a good idea to use anti-seize (or grease) when screwing steel into something else.