Arnold did EXACTLY what the judges(and Weiders) were saying they wanted to bring the sport mainstream. You have to remember Zane is the guy to knock out, champ 77-79 and he would be considered a bit thin for men's physique today. Bodybuilding was starting to go mainstream, the health club boom was happening, and Ben Weider was thinking of bodybuilding as an Olympic sport. They were pushing Zane physiques. Lou was smart to get out when he did.
Arnold at 6'2 could have easily come in much bigger. He was competing to win, not be the most jacked. The other competitors had a bit of a revolt and said fuck that skinny look. That's what the whole argument was about the weight classes. Arnold wanted the weight classes, so at the overall he'd be posing against the lighter weight class winner like he always did. The other guys, led by Mentzer, wanted him to stand against the big boys. The judges were put in a tough situation.
The 80 Olympia was like Leonard Duran 2. Leonard fought like a bitch, but that's what it took if he was to win. Arnold came in thin and aesthetic. And took the Sandow, and heard that lamentations of the women saying it was rigged.
Remember, THIS(guy on left at 195 lbs) is what the 79 judges said they want for Mr. O.