Also, such rhetoric is not needed, and is not beneficial to Clinton.
"Secretary Clinton, some in your party are calling on Senator Sanders to drop out of the race at this time, to help unify the party. What is your take on that?"
"Well, first, I'm very confident - and not just me, but pretty much every analyst who looks at the numbers agrees - that my campaign will maintain the strong lead we hold in pledged delegates, and I will be our party's nominee in Philadelphia in July. That said, it's important for the party, and for every state to run its process, and for every voter to have their say. The party will be unified at the convention, and through to victory in November. Senator Sanders has obviously inspired a lot of Democratic voters, and we look forward to not just defeating Donald Trump in November, but to a USA that rejects the politics of fear and hatred and divisiveness for generations to come."
What awfulness would happen if the Clinton campaign were to be engaging and confident toward the Sanders campaign, rather than nasty and vindictive?
The divisiveness is coming from the Clinton camp. It's who they are and how they operate.