The second half of Luthen’s conversation with Saw is him trying to convince Saw to lend air support to another faction so that they can make a combined hit on an Imperial power station. In rage, Saw tells off Luthen for calling his adherence to his own ideology as “petty differences” and says that he’s not risking his people for someone else. Saw has a reputation for being an extremist, and Luthen knows that his operation is well-funded and successful. Saw, however, is right to refuse the tactical alliance.
I'd like to add that the doomed faction Luthen was trying to get Saw to support were remnants of the separatist forces from the Clone Wars. The Separatists were often coded in fiction as the Confederate side of the US Civil War by emphasizing their role as the aggressor and their colonial / race-supremacist / pro-slavery politics. Names in Star Wars often are linguistic and historical references, with Gerrera being both similar to Guerrera (warrior in Castilian) and the character is directly inspired by Che Guevara, for example. The name Anto Kreegyr conjures the German word 'Krieger' which also means warrior. This is perhaps intentional to draw a comparison between Saw and Anto, both warriors and rebels, but with very different implied motivations. Anto is linguistically similar to Anton, a common Slavic name. The German language is unfortunately closely associated with the Kaiser during WWI and Nazis during WWII to English audiences, and Russian is similarly associated with the authoritarian Soviet Union.
The implied subtext is that the opportunist Luthen wants the anarchists to work with fascists and authoritarians in the name of defeating a greater fascist threat. Saw's outrage at the suggestion is much more reasonable given this interpretation, as well as his eventual decision to permit their sacrifice to increase the chances of ultimate victory.