I'm certain that she fully expected what happened, given that she could at any time change her mind and talk to them. I have a great deal of respect for her standing up for her principles, even though I'm not so sure about Assange at this point.
I'm entirely with you on both. She thinks the concept of Grand Juries if wrong and should be eliminated. In reality, it would toss the existing US legal system on its head. I don't fault her one bit for sticking to her guns, but actions have consequences. She's super smart and obviously knew she'd get jailed for contempt of court. However, that does sort of play into her "they treat me awful" narrative.
IMO, Julian deserves a lot harsher sentence than Manning, but what he's been indicted on thusfar, is pretty week with a max federal sentence of only 5 years. I fully expect the prosecution to use this to bargain with him for a plea (and info on Russian election tampering). Their dangle to him would be a whole slew of superceding indictments they'll almost certainly have him dead to rights on. Guccifer 2 has been proven by Mueller's indictments to be a GRU (Russian Military) intelligence operation. Stone, Julian, and Guccifer 2 were all pals. That's not a good place to be when you're in US custody.
If anyone else did the same, they'd get the same result for contempt of court. While I respect her peaceful protest, what did she expect?