This is politics, one is permitted to ask for motives. It's not a search for truth, it's a quest for power.
FOIA requests are as “search for truth” as you can get.
Deleting staff emails days after they depart or asking people to email your private Gmail account is impeding any and all searches for truth.
It's okay for government to delete emails if the Good Guys want it but not the Bad Guys want it.
How closely do you need to scrutinize the ACLU's motives.