3. Most of his fights are poorly documented.
Despite having only fought a handful of times, a solid chunk of the documentation is anecdotal or straight-up hearsay. Considering the significant legend status all of Bruce's hagiographers have produced, it's hard to know what to believe.
4.There are rules in the ring, not so much on the street.
Lee's training and interests were almost purely utilitarian, devoid of considerations to a ring, mat, or any kind-of-gon. If anyone had ever wanted to put a "Bruce Lee vs [whoever]" they would have had to do it with restrictions, because a fight to the death isn't really an option.
5. He was an actor.
To many people, this is damning evidence against his skills. It's unclear why, but due to its near bacterial presence on the internet, it seems worth a mention.