The Hathaway taxi drive isn't necessarily against fighting the Federation
His criticism of Mafty is specifically because of his message ("he's too egg headed though".) The lack of direct attacks on manhunters ("I wonder why Mafty doesnt strike back") and the environmental motive are where Mafty looses this guy. Him not understanding why Mafty is obsessed with going to space and saying hes too busy working is indicative of Mafty's failure to gain more popular support with his messaging.
This is more of a criticism of idealists whos messaging doesnt connect with everyday people's concerns and and why no one cares about the environment. If Mafty's explicit goals was to fight the against immigration death squads and unfair permits, this guy would be more supportive of Mafty. Its why populist messaging is critical for a revolution to succeed. Its more complicated than simply "shut and get a job like the rest of us."