Who made it public? you can just blame Feinstein if you want, but it is not known.
We do not actually know if the letter WAS leaked...
...or just news that a letter existed...which precipitated making the letter public.
Anyway, these assholes keep moving the goalposts. This conversation did not start out talking about the letter being leaked...or by whom.
It started with a question about WHY THE INVESTIGATION DID NOT TAKE PLACE EARLIER.
In essence, that would have required that the letter be made public...which Feinstein would not do. The person writing the letter, Dr. Ford, asked that it not be.
They know that...but they have so little to go on...the pretense is needed.