RE: The Silencer: hero or antihero?
I always believed that since there's no proof that Silencer, while on a mission(s), saw anything that would contradict the WEC propaganda that he's been fed with since his early childhood, he was simply rational and joined the resistance as he had nowhere else to go. There are two main reasons I believe so:
1. Seeing how much is everything under the WEC control the Silencer knew that they would hunt him down and eventually kill him. To make things worse, not just WEC, but the Resistance is also very "sensitive" to WEC-labeled soldiers in a red suit, so he had basically nothing to lose by going over to the Resistance. Aside from that, I don't think Captain could just "blend in" with civilian population (even without his bright red suit) as he was removed from society while he was still a child and bred to not have a real social life.
2. The only way he could take on the WEC, and eventually revenge the death of his squadmates, was by joining the Resistance.
Now, because of his "fatal flow" (how Dr. Hoffman described his lack of ultimate loyalty to the WEC) I believe Captain accepted the cause that the Resistance is fighting for and he TRULY became one of them ( a "full-time member" so to speak). I mean, after doing certain missions, seeing things, and then seeing what WEC NEWS was saying (lying) about the actions of the Resistance, it is safe to say that he realized what's really going on in the world and who are the real bad guys.
the best part is, as you said, that it comes down to the player to interpret motives and immerse into the role of the Silencer. I think many of us who played the series really wanted to see WEC and Draygan burn not because we wanted to avenge our fellow Silencers, but because we accepted that WEC is bad in the every sense of the word.
So, to answer your question, I think that Captain initially "fought the proper cause for the wrong reasons", but eventually "saw the light" and started fighting the WEC because he believed he's doing the right thing.