Could it be that they need us?
Yes, as a matter of fact. Dubai's oil reserves are estimated to run out in 2016, so for the past several years, Dubai has been looking for alternative sources of money.
Without the port deal, Dubai can and will certainly look elsewhere for U.S. cash flow. This threat of retaliation from one of our allies (delivered to us by an anonymous source--convenient, eh?) smells like a bluff.