What does "unloading on Assange that her 2016 rival was still very much on her mind."(1st paragraph) mean?

Context>>>>>>>
And, while the former first lady technically made good on her promise earlier in the day not to mention President Trump by name, she made it clear while unloading on Assange that her 2016 rival was still very much on her mind.

"It's clear from the indictment that came out that it's not about punishing journalism," she told attendees and moderator Paul Begala, referring to the Assange case. "It's about assisting the hacking of the military computers, sealed information from the United States government. And, look, I'll wait and see what happens with the charges and how it proceeds, but he skipped bail in the U.K., in Sweden had those [rape] charges which have been dropped in the last several years. But, the bottom line is that he has to answer for what he's done, as has been charged."