Malak says on Dantooine (the first star map they found) "are you sure you want to go through with this, after this there is no turning back" or something like that.
They were well on their way to the Dark Side.
They found the Star Maps after Malachor V, during the time they were in the unknown regions, or supposedly in the unknown regions. During this time they had already converted their army, which includes a lot of ex-Jedi turned Sith and god knows how many soldiers. The Exile speculates that Revan used Malachor V and the mass shadow generator to destroy the parts of his army that weren't loyal to him and that wouldn't turn to the Dark Side.
Seeing as they found the Star Maps after that, we know that Revan was indeed on the Dark Side and had already converted people. He would have done the same with Jolee if Jolee was of importance, obviously Revan and Malak felt that Jolee could stay there that he wasn't a threat and probably just not worth their time or effort to kill or turn.