It wasn't just petty and paranoid, it was strategic thinking that Machiavelli would endorse. She succeeded in winning the party battle in the primaries based in no small part on long-term strategic moves like this, however repugnant her goals or her self may be. But winning the party battle also left her too far out on the Left to win the Rust Belt states who had been on the losing end, or at least gotten nothing of value, in so many Obozo-era Progressive policies.
Adding to your thoughts, her hard-ball tactic gained her the endorsements that helped her win the party nomination, but I think it cost her the enthusiastic support that could have helped her in the several states that were close. People who are squeezed do what they
have to do, but they don't love the one squeezing them.
Distancing herself from BHO was an all but certain lose-lose choice. Distancing herself from BHO risked losing a 90%+-loyal segment of the D base. OTOH, BHO had screwed over what had once been a very large and faithful segment of the D base, working people (
all "colors", wage earners
and small business owners), people from whom most of Hillary's peeps kept her isolated.
Hillary chose to mostly affirm BHO. The "black community" weren't Hillary-enthusiasts, and Trump got more black votes than Romney or McCain. The voters her campaign ignored and promised to keep screwing over (the way Obama did) rejected her.
