Ronnie just has an extreme southern drawl. Compare him to most bodybuilders and he's obviously very intelligent. Think in terms of taking care of his health, financial planning, being respectful to his competition, adapting to his environment and so on. How many pros get complete health panels done every two months?
I think people really have no idea what true intelligence and true confidence really means. Example: Ronnie is very intelligent. The sound of his voice has nothing to do with judging that. Arnold in Pumping Iron was not confident as so many say he was. He was just an asshole exploiting the weaknesses of someone with a disability who was emotionally depdendent on his father. Arnold would never have been able to pull that shit with Franco because he was too intelligent.
If I was in Pumping Iron I could have made Lou my bitch too. It's not like that was a difficult task. Now let's see Arnold pull that with someone who is intelligent - it wouldn't have happened. Franco would have probably laughed at him for even trying it.
It may be somewhat off topic, and I'm sure you probably know this anyway. But for the benefit of those few who are still unaware...
Although Pumping Iron is technically a "documentary" with plenty of realistic elements to it, it's pretty much common knowledge nowadays that the movie was heavily scripted. The 25th anniversary edition that came out a few years ago showed quite a bit of behind the scenes footage on the making of the movie and also had fairly recent interviews with Arnold, Lou, and most of the rest of the cast.
Among many of the revelations was Arnold admitting that such things as his claiming to have not gone to his father's funeral due to his focus on an upcoming show was complete bs. It was something that was scripted in order to make his character more "interesting" or whatever.
The filmmakers also talked about how they scripted this Arnold vs Lou thing as sort of a "David vs Goliath" or a kind of an attempt as a "Good vs Bad" scenario - sort of the WWE type of drama. If I recall correctly, they originally wanted to portray the dark, brooding, larger Lou as the "villain", and Arnold as the good guy and underdog. If that was true, it certainly didn't work out that way. For obvious reasons, the exact opposite impression came across on-screen.
Lou even wrote (or more likely had ghostwritten) in his autobiography of some of the unrealistic embellishments of the movie - mainly that the apparent close, supporting relationship he and his father had in the movie was a sham. He claimed that his father was always an obnoxious, psychologically abusive egomaniac who insisted on being part of the movie to satisfy his own selfish desires. Of course I realize that there are two sides to every story, and I tend to take anything Lou says with a grain of salt anyway - for obvious reasons.