It seemed as if the remaining Original 8 alliance members were intent on keeping the alliance strong with an exception of Dana. As a result, most felt that Jee should have nominated Dana rather than Erika, who has given nobody cause to fear she is straying from the alliance.
When Jee refused to nominate Dana, and threatened to put Jack up if the veto were used, the alliance members did the only thing they could at that point, and booted Michelle.
From a personal observation, I believe Jee did a HORRIBLE job as Head of Household, and allowed Justin and espekcially Robert to dictate his decisions.