Comparing nations to states is ridiculous. However, if you read the report it's damming with faint praise. "the average connection speeds seen in the United States and Mexico remained more than twice as fast as the next fastest country"
Sure, if you discount everyone that's better than you then you can call yourself #1 at anything.
PS: Note this is of course average bandwidth which radically distorts the picture. One person nominally at 1GBPS and 10 people at 1MBPS is not the same as 11 people at 90+MBPS. For a more realistic vew you would average the square roots of bandwidth, but that makes US look bad.