Do not agree with that at all. Movies are always about interesting people in interesting situations - you said it yourself.
The mob was comprised of very interesting people because they lived by their own rules, but as it is shown, they’re objectively pieces of shit.
Goodfellas shows that they all pay a price for the way that they live and the movie tells that story. There is nothing glamorous about being in prison or being a strung out paranoid loser drug addict. Nothing glamorous about worrying about getting murdered by your only friends or getting executed by your own people. Nothing glamours about being in witness protection.
That’s where these guys all end up, and Goodfellas is a movie about that arc. To me it’s just telling the story. Anyone who watches that movie and likes the characters or roots for them is an asshole. They’re scum bags of the highest order.