That was a great scene and much larger than just the two characters.
Sure, we know the inside track of Picard's ordeal with the Borg and how it happened and what happened.
But for the general public, and probably most of Starfleet, all they know is a starship captain was captured and turned by the Borg to fight against Federation forces and wipe out thousands of lives at Wolf 359. The starship captain was eventually rescued and returned to starship service.
How much more would people really know?
I'd bet Sisko wasn't the only one who lost loved ones and held a grudge against this starship captain Picard.
Look at the reaction Kirk got from his collegues over the loss of Finney. Imagine the reaction Picard probably got over the loss of thousands.
Sisko wasn't alone. And that scene showed a bit of what was maybe a lot of resentment and anger held by a lot of people in mourning over Wolf 359.