Of course Alito was right because this regulation was not overturned by the current decision as Obama alluded to. In fact, as you state, it was not addressed by the recent decision because it was not what was under consideration.
The current decision was whether McCain/Feingold from 2002 was constitutional, and it was decided that due to it's nature, it would put a chill factor on free speech.
So constantly alluding to a regulation that was not even under consideration is a red herring.
Now to your question of whether an American owned company or a foreign owned company can donate to campaigns where foreign owned companies are banned, then if the definition making a company American owned is 51% is still law and still on the books, then it is still "legal", no matter how much ownership is foreign. If you are going to start defining only public companies that have no foreign ownership can contribute, which in most cases is stock ownership, you will by that reasoning, ban almost all publicly owned companies from being able to donate under the rules of 441, as stock ownership is open for any investor. That would also mean that you would have to determine if there is any foreign ownership of any mutual fund that may have a percentage of the portfolio of a company.
There is a reason for the 51% ownership is that the 51% ownership has the controlling interest; thereby, making any public company that is 51% American owned and still controlled by American interests.
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