You are correct in saying we Harari's mix culture and religion. You are 100% incorrect in saying it is mostly with the American Harari's...
Our culture has confused the religious obligation of a marriage with our created customs... and these mixed practiced are predominantly practice back home. When the religion very simply requires a dowry ( prize gift) for the wife of some substantial value... we go overboard and add several other things, and the danger is if you ask a Harari what you need to make an Islamic marriage they dont know what is the religion or the culture. All the gold, money and clothes are not part of the religious requirements of a marriage, yet this custom has been part of our culture (which started back in harar) and confuses people with what is required from the religion.
How about "our music"... you say its an American thing but where are most of the popular Geyusu artists from??? Harar!!! Is it ok to be playing those instruments and singing about love and romance??... and how about all the dancing that goes on in the weddings??? That was not invented in America. That was adobted back home.
In retrospect, we Harari are better off than many other cultures in terms of mixing religion and culture... however, we must not let our cultural practices interfere with the true religious practices. If we know having men and woman dance together at a wedding is Haram (which it is), then why cant we put our love for pleasing Allah ahead of our pride (admiting we are doing something we should not)...
Rather than putting the blame on "American Harari's" ( when they are no more at fault that the ones back home), we need to unite as a larger Umah and ask Allah for the strength to do what is Halal and refrain from the Haram... being Harari does not give us a pass to paradise, being a true beliving and practing muslim does...