Let's keep in mind that the port issue was a transfer of assets between two foreign companies that happen to have operations in US. There were only two bidders for the British company assets in US. The company with the highest bid secured the assets and then the government interfered.
Oh, I understand exactly what the port issue was all about.
The original poster wrote, "That is because the U.S. is a capitalist nation that enforces laws and contracts. Investments are safe from nationalization and seizure by government...", and the ports deal belied that claim. Dubai Ports World made a legal investment, purchasing contract rights to operate US ports. The United States Government made it clear that those rights were to be voided.
The fact that the US didn't strictly nationalize the ports contract does not mean that seizure didn't occur. Every potential purchaser of those ports contracts understands that Dubai is a 'motivated seller', and can use that fact to their advantage in negotiations. A seller can't obtain top dollar in the case of a fire sale. The difference has been taken by the US Government.
This taking is really not that much different from the imminent domain ruling which produced an uproar here recently, allowing government to take from one private party and give to another private party. The main difference is that the taking is not from a US citizen, but rather a foreign entity.
The original poster was speaking of exactly those types of investors when claiming that, "The U. S. is one of the very few places on Earth where it is safe to invest large amounts of money" for the reasons I quoted above. In fact, in the case of the ports deal, the US proved not to be a safe place to invest a large amount of money, because the US declined to allow continuity of a legal contract, and proved that investments by foreigners are not safe from 'patriation' and seizure by government.