There are lots of resources that describe the influence of Scots and those of Scottish ancestry on the development of the US. Of course, to expect any Highland traditions (or any other traditions) to remain distinct is to ask for disappointment. The US is built on the blending of traditions and cultures; anyone ever hear of the "melting pot".

The real problem comes when people think that the blended traditions are the same as the original. To think that highland games in the US are the same as those in Scotland is just misinformed and a bit foolish. Of course, there are a lot of misinformed and foolish people in the world.

Just as what many in the US think of as Italian food isn't really traditional Italian food, but rather a blend of Italian and the myriad other cultures encoutnered in the US, so too are the highland games a blend of the original concept along with other things.