Why is there a Holocaust Museum in the USA?

Why is there a Holocaust Memorial Museum in the USA (D.C.)?
1. The holocaust did not take place in the USA.
2. The victims were not US citizens. Sure, some of the survivors later immigrated to the US, but so did other victims of the war from other countries (France, England, Poland, etc).
3. The US did not take part in it. The US entered the war for other reasons before the holocaust started. The only way the US was involved in the holocaust was because their fighting helped end the holocaust and free the victims. Although, it has been speculated that if the US had not entered the war, there wouldn't have been a holocaust.

Thus, it seems like a strange event for the US to memorialize. It seems like holocaust memorials belong in Europe and Israel, but not the USA. Is there any other memorial in the US dedicated to non-US citizens whose hardships occured in foreign countries? I can't think of any.

If the US is going to memorialize holocaust victims, why not memorialize the other victims of WW2 (French, English, Slavic, Chinese,...)? Why not memorialize the South East Asians who suffered in the Vietnam war? I don't see a difference.