Is saying your black coworker under-performs a form a racism ? Your female coworker being stupid would be sexism (but only if you're a man of course) ?
So will this come down to any email which passes through an officially recognized organization, be it government or corporation or educational, as open to inspection and possible litigation? Talk about an Orwellian nightmare
The person you are suggesting has the right to privacy is acting in an official capacity, paid for by public money. These are not personal emails.
Just that fact that one person is bringing a litigation, is not a valid reason to mark everything top secret.
If you make everything in the machinations of government secret, then these things (and much worse) will still happen, but there will be no transparency or recourse. That is the worst possible outcome.
Ignoring the legal arm-chairing; universities and colleges retaining staff who discriminate students based on intellectual disabilities could face down some bad PR.