I don't understand how you can claim this is a futile gesture. If she doesn't want to talk on the record, or state things which might involve snitching on someone I find that to be an admirable action to take.

By the end of the grand jury she will be freed, and she will be freed with the moral high ground. If you think having morals about not snitching is 'futile' that is your choice but many people take it very seriously.

Manning is willing to talk on the record and "snitch". She just doesn't want to do it behind closed doors. But all grand jury proceedings are done behind closed doors for good reason. Manning has no moral high ground here.

Secret proceedings simply shouldn't exist. I think personally that grand juries that are allowed to hold people indefinitely because they don't want to talk in a secret proceeding is wrong. Also, if she talks in a secret proceeding nobody will know if she deliberately said something incriminating aka 'snitched' or just gave innocuous information.

Since her giving secret testimony would raise doubts as to whether she snitched or not, she wants to do so openly in order to maintain her public good-will as a non-snitch. I think you are mistaken in saying that she doesn't have the moral high ground here. These proceedings should be illegal in this country, you shouldn't be allowed to hold someone for unspecified sentences to torture them into talking. That isn't how testimony should be gotten. I'm appalled by some of the opinions here.