Is power lifting some kind of trendy excuse or innuendo I'm not familiar with?
Arnold is 6'2" and weighed 235-240 as Mr Universe.
Arnold also cut a lot of weight in the weeks leading up to the competition to look so defined. His training weight was around 260-270.
Bodybuilding is very different from powerlifting. In powerlifting your goal is to be strong, not defined, so having fat isn't necessarily a bad thing - although you do compete in weight classes, so there is motivation to not be a fat tub of lard.
I tend to follow bulk-and-cut cycles, not terribly unlike a bodybuilder's routine. When I'm competing in the 165 weight class, I'll generally bulk up to around 175, building muscle/strength along with some fat, and then cut down to competition weight in the month leading up to the meet. Similarly, for the 148 class, I train a bit closer to 160.
Either way, the point of bringing it up is that BMI simply accounts for your body mass, not your body fat. A powerlifter may not be as ripped as a bodybuilder, but chances are a large amount of their weight comes from muscle mass, which means their BMI is going to be very high, and not an accurate scale of whether or not they are healthy. In my personal example, sure, there is fat on my body. I don't have a six pack. But it would be silly to call my weight unhealthy, even when I'm in the 170s.