You're right about one thing, I like to have the last word. Now, I don't always have the mood to waste time on internet arguments, although I do at this moment so I'll take my time to debunk your stupid arguments.
First, gangs are not "rooted in evil" in the series proper, eg Bucciarati who seems to actually have a good relationship and did services for the people of his territory. Giorno envisions the ideal gang members as local protectors of the weak, even though he also is ok with some crimes. We can argue how bad is his worldview forever, but that's better than drug dealers who don't give a shit.
Secondly, this theory about Giorno being corrupted by his business, that only works for ordinary people who'd fear for their lives or can crack under pressure. He's the most powerful person in Europe, with a Stand that can protect him even if he isn't aware of a danger. He's also a person of exceptional character, whose moral code is grey but iron-clad, and with a talent for charisma. Everything after killing the Boss is actually gonna be easy for him.
Do you think Giorno is gonna be simply taking over and not do anything to the old members of Passione? An organization is only evil when its members are evil. He'd intimidate any grumbler with his all powerful Stand and any dealer is gonna be executed. Plus, he'd recruit new blood, rough but decent people to become gang members like Bruno did. He could even turn them into Stand Users, because he's got the Arrow in the turtle, don't forget that. With all the money, he'd do sincerely what several prominent criminals do: spend it for the community, renovate stuff, have public infrastructures made, donate to schools or hospitals. With the probable support of a group of Stand Users and the public, I don't see Giorno being endangered by any rival gang in Naples or anywhere. The government? He'd find the good people in it and support them, cooperate with them so that they also change things too.
That's all I'll say on the matter.