Jeremy Crawford wrote the following:
The mind blank spell is meant to protect you entirely from the feeblemind spell.
Yet, according to the description of Mind Blank, the spell only protects against these effects:
- Psychic damage
- Effect that would sense emotions or read thoughts
- Divination spells
- Charmed condition
The Feeblemind spell does the followings:
- Inflicts 4d6 psychic damage
- Sets a creature's Intelligence and Charisma scores to 1
- Prevents spell casting
- Prevents magic items activation
- Stops language understanding & communication
Only the first of these effects is explicitly stopped by Mind Blank.
Why would the other effects be nullified by Mind Blank?