It's not I like him, but Jun Seros and the chancellor are far worse to you. They framed those crimes to you and launched those cruel operations. You had your chance to avenge yourself because of Darth Tormen's help.
Remember those BH who got killed by the Jedi? And your companion got kidnapped because of those framed crimes.
the jedi killed the other hunt champs. The chancellor, like most politicians, did not look into the matter and just did as the jedi said. Plus, keeping the Chancellor alive, showing the reublic that you're not completely in the empire's pockets, means i can play both sides and, hopefully, acquire bigger credit opportunities.
Murdering others is a disservice to your fallen comrades. Jun Seros was the responsible figure, the Chancellor was just an inept chancellor.