Exceptions to the rule do not negate the rule itself. The NBA does have the best players in the world and the league is generally considered to be the highest level of competition for the sport and therefore could reasonably argue that the team that wins the championship each year is the best in the world. Noah’s comments come across as more just sour grapes.
The reality is that’s its all subjective and none of this matters. You can make a reasonable argument that NBA champions are world champions, you could make a reasonable argument they are not, and you could make a reasonable there is no possible way to concretely determine a “world champion”.
Moreover, outside of apparently running sports and Europe, no one cared about this until Lyles made these comments. Everyone is getting riled up because some guy with sour grapes was being pedantic. At the end of the day it really is just a marketing term that means nothing.