Is "detailed" audiophile code for too much treble?

Brightness and detail are two separate issues, although often finding both in some systems.  Also, people have different tolerances for brightness.  The fix is better/different components. 

Increased detail can be nothing more than dropping the noise floor with better components or better room absorbing/dispersion control.

Brightness can usually be traced to the high frequency transducer, offen experienced with metallic tweeters like beryllium, but not all metallic tweeters sound bright- depends on the execution.

Another way to look at this, does “reality” have too much detail? Barring the use of excess hallucinogenic drugs, the answer is “no”.
High-end audio is simply a facsimile of reality, so you can have detail without the shrillness - it all depends on the execution

For those who are sensitive to bright/strident sounds, I often think one solution is a “soft” dome tweeter.