why do americans only pay attention to weightclasses they are doing good in?????

This is a ridiculous thread, you're just talkiing about the casual American fan while i'm sure you will find some exceptions there as well. Its like that in any sport though, the people who don't follow that sport religiously will only interested in it when they have a reason to be. It was the same over here when Dunne won the world title, everyone was talking about him but those people couldn't tell you anything about the other weight classes. Its just highlighted more with Americans because America is watched more closely by the world than anyone other country.