CS can validate without knowing the details, the same way you don't enter a password and then check to see if that matches the password in the system.
The fact that they keep blaming overseas customer support is pure blame shifting - you still hired someone and gave them access to all this data, Coinbase!
Where do you see blame, this is a fact and it's relevant.
If they didn't say this, there would be pitchforks out about not giving enough information.
We don’t know if they had access to everything. They got data for “less than 1% of monthly transacting customers”.