OP is about freedom, and fighting against opression from WG. WG killed everyone who knew Roger. Like if you want to use brain then you will get the answer who was the real villain of the series:
1. Shichibukai - WG dogs, almost all of them was Luffy's enemy;
2. Marines - WG lapdogs, who sink in the corruption, and was Luffy's enemies from East Blue arc;
3. Celestial Dragons killed "Sabo" and created all this burning of lower people;
4. WG destroyed Ohara;
5. WG stand behind human auction;
6. WG killed Ace;
7. WG defeated Joy Boy;
But the FV will be BB, who comes from D. clan, that was WG enemy, right. That's makes sence. Also this is why author makes Teach so weak, right.
1: If OP is about freedom and fighting against oppression from the WG, why was the longest arc Wano, which was entirely run by a pirate? If WG killed everyone who knew Roger, why are Rayleigh, Gaban and Crocus just chilling?
2: Warlords aren't WG dogs, nearly all of them betrayed the WG, and plenty of them helped the SH, Kuma, Hancock, Mihawk
3: Yeah Marines are important in the story, I agree with that
4: yes, the WG destroyed Ohara. but one of the most important Marines in Ohara is literally in the Blackbeard pirates
5: Luffy doesn't really care about slavery unless his friends are affected, and Blackbeards islands probably have slavery too
6: Yes the WG killed Ace, but that doesn't mean they're the only reason Ace died. Blackbeard turned Ace in, while being his former crewmate, which is the kind of thing Luffy hates the most. Shanks personally went to WB to warn him about Blackbeard, and WB disagreed because he believed that Blackbeard committed the worst crime on the seas(for a pirate)
7: if you tried to explain to Luffy who Joyboy is he would fall asleep