I see absolutely nothing wrong with this situation. A company with a very good record for port management all over the world purchases another port management company. Normal business transaction.
The UAE have been allies of ours for a long time, and show no signs that they will not continue to be. The uproar over all this is paranoia and has significantly racist overtones.
Oh, and by the way, these operations have very little to do with port security. That is still a government function, headed by the Coast Guard.
