I may be mistaken, but I seem to remember a lot of anger from Picard, and even Guinan in I, Borg.
And Picard's failure to infect the Borg with a virus, using Hugh as a carrier, raised the ire of Starfleet admirals. So there would be some who suspected that Locutus was still compromising Picard, but they couldn't prove anything. So they kept him away from the Borg.
"Descent" took place after this, and Picard and the Enterprise were right on the tip of the spear there.