The terrorists are entirely justified in their violent resistance against the obviously evil and genocidal Britannian empire, which is something of a stand in for both the British Empire and the US.
The annoying liberal deuteragonist bumbles around for 2/3 of the show being a supersoldier for the Britannian Empire while constantly making these bizarre self righteous arguments that Lelouch's rebellion is just too darn mean and violent, we have to support the Britannian Empire's rule of law just a while longer guys! The longer this goes on, the more and more his world view crumbles around him as basically nothing goes to plan for this liberal who is just incapable of grappling with material reality. He ends up following his sense of liberal morality all the way to accidentally killing millions with a Britannian wunderwaffe nuke. This leads him on his jokerification arc wherein he realizes the error of his ways and actually supports Lelouch through the batshit last few episodes of this show.
Anyway, I can't recommend this show to anyone in year of our lord 2024 because it's obnoxiously, embarrassingly horny in a very mid 2000s anime way, because that's exactly what it is. But I'm imagining what could have been.
I mean lelouch technically did the same thing by working within the system but instead of slow incremental change he just overthrew the king and psych forced everyone.