When I was about 17 I was told my bmi was 25 and I was apparently overweight. I certainly am now but then I did bike racing and played football and was very fit. I think just because I had a slightly stocky build the bmi looks skewed. For someone as stocky as Tyson I could see how his bmi might be classed as obese. That isn't to say I don't think he was on anything, 95% of top athletes are on at least some semi - legal protein product or other in my opinion, if they're not outright cheating.
Normally, a BMI like that can be seen for shorter stocky man. Sullivan (made way less) and Tua are others for example. The super "stretched version" of this is Ike Ibeabuchi at 6'2" and at a trimmed 240, which is ridiculous. At comparable low body fat % of athletes, the remaining variable of the BMI is a good indication of physique or "stockiness factor".
On top of what's already been said, Tyson is one of the greatest boxing nuts of all time. Fighter's who know their history probably can't tell you about guys like Tommy Burns or Kid Chocolate.
After Ali retired, the focus shfted to the lighter weights, Leonard, Duran, Hearns, Hagler, Benitez, even Ray Mancini. Tyson brought back the focus on the heavyweight division.
He saved the heavyweight division imo back then it's got to be said. As good as Holmes was, he hadn't lit up the heavyweight s, and the alphabet boys..?.. Say no more. So when he came along bursting on to the scene, it put the spot light right back on the top division.
Casual fans love the street thug persona. They also believe the hype that he was the best ever and aren't even aware of how bad he was later in his career.
It's that part where he looked brilliant that people latch on to, that time up to Tokyo. After that im afraid to say it's picking the good bits out of a messy pie.
He had crossover appeal because he used an ultra-aggressive style and tried to take his opponents out with every punch, from the opening bell. He was also very young when he arrived at the best heavyweight on the planet, and that fascinated people, this "kid" of 19, 20 years old. The reason people still watch him now is because of that crossover appeal. He appeals to the most casual of sports fans.