Were good and bad people present on both sides in all the other major conflicts in the series where the Strawhats were involved? It mostly ended up with good people banding together with the Strawhats and against the oppressive forces at play.
I don't see any of Smoker, Tashigi, Koby, Fujitora etc. sticking with the WG.
Yes there has been.
They just had different people they believed in.
King and Kaido aren’t bad people, Kaido has very similar ideals as Luffy and King isn’t a bad person either.
Katakuri wasn’t a bad person either, in fact most of the BMP aren’t. Not even Big Mom.
Mr. 2 was a good person and still fought against the straw hats.
Magellan is also a good person who nearly killed him self after his epic failure of having these dangerous people back into the world.
Hachi was a good person in arlongs crew.
Perona and Moriah also weren’t bad people.
Wadatsumi wasn’t a bad person
I can go on but this is just my initial thoughts. The straw hats don’t just beat bad people. They never have.
Hell look back at the very first arc where the marines stood behind Morgan despite him being a bad person and them being good people