She had a bunch of advantages over Obama.
She was experienced in DC.
As a wife, not as an official. They both only spent a short time in the Senate, but Obama was considerably younger.
She had clout and was a top predator in The Swamp. She had Slick Willy to back her up, help her plan stuff, and do her dirty work when necessary.
So you are saying that President Clinton was not willing to help Obama out?
They practically owned the DNC, far and away the most formidable power in the non-governmental world.
And that was a problem. DNC tried to manipulate the 2016 primary and it backfired.
How was the 2016 primary rigged?
So, this one isn't entirely wrong.
There was, among the DNC, what amounted to a betrayal of progressive interests by failing to at least play a "fair" campaign against Sanders.
Instead things turned ugly, and a lot of bad blood spilled across the party over it.
This bad faith that Hillary displayed owing to her clear sense of entitlement to the nomination was a powerful message to progressives that their concerns would be disregarded and it really hurt Hillary.
The GOP successfully pitched her as an entitled legacy hire (despite the fact that Trump was, himself, groomed for his eventual use in politics), and so it felt, even as someone who voted for her, more like a chore than a blessing.
See also how Pelosi blocks progressives from being nominated to important positions.
Remember that when conservatives use a word like "rigged" it has a shifting meaning: when discussing Dems, it means anything including refusing debates and trying to prevent Bernie from having political capital.
When discussing elections, it's not even "rigging" when you literally prevent the votes from being accurately counted and have the courts give it to an unclear victor.