Recommended reading

"How Equal Temperament Ruined Harmony (and Why You Should Care)" By Ross W Duffin.

He explains the whole business of temperament and the various attempts to find a "satisfactory" tuning system for fixed pitch instruments.

All tuning systems are a compromise and equal temperament is just one of many. Duffin does not say it is wrong or unsatisfactory just that it is inappropriate for music composed before the 20th century (IIRC).