So who put the material there? Had to have been...Herself.

What do you imagine the classified information to be? These weren't stand-alone files or documents that she brought home from the office. Per the inspector general's report, the classified information that was on her servers was information that was contained within the body of, or attachments to, emails that she received. Several instances involved classified information buried deep in the body of an email chain, many many forwards before Clinton received a copy of that email.

There's no evidence that any of it was put there by Clinton herself.

You can't send that kind of material from a classified network to an unclass network.
When you have access to that kind of material, you can only send it to people who are inside that particular network. Someone has to remove it and put it someplace else.

Perhaps - but in order to prosecute Clinton, you have to prove that the someone was Clinton. And considering that the classified information was part of or appended to incoming emails to Clinton, there's not going to be any evidence.

That's hilarious.

What's hilarious about it? You can't convict someone of a crime unless each and every element of the crime is established. The obstruction of justice and destruction of evidence statutes apply only to specific proceedings - and legislative Congressional inquiries aren't among them. They apply to agency and law enforcement proceedings, and Congress is neither. It is a legislative body. You aren't committing the specific crime of destruction of "evidence" if you delete documents in order to avoid a legislative enquiry.