One cannot ignore that they did their later work here. Not there. As did many others whose own societies collapsed or otherwise failed them.
In any case, I’m arguing a narrow argument: that a company like SpaceX could only have been founded, when it was founded, in America. Because of its certain characteristics that are an exception in the set of the world’s cultures. (One among many: its unique ability to assimilate and positively appropriate from immigrants.) That doesn’t mean it’s faultless; that’s a straw man.
The US is not unique in that regard. Australia and New Zealand are very comparable in that way. Canada probably belongs in that list too.
I agree that, in the contemporary world, SpaceX could only have happened in the US. But that's because of economic factors (government funding for the space industry, easy and plentiful access to venture capital, a low regulation business environment.) That particular combination of economic factors is unique to the US. Being exceptionally welcoming to immigrants is rare but not unique.
https://en.wikipedia.org/wiki/Operation_Paperclip
In a more just world they would have stood trial in Nuremberg.
Yes, SpaceX could only happen in the United States. But let't not pretend that the whole American package warrants the 'favored and exceptional nation' badge that so many seem to want to bestow on it, which is what this American exceptionalism is all about. Shining city on the hill and more of that kind of crap.