Interesting point. If this health care worker was truly contagious, would have been in contact with potentially thousands of people in the gate areas, restrooms, airport vendors, public transportation, and so on. In fact, more likely to have infected some other people with direct contact than those who were on the plane.
I mean the news of this person travelling is bound to be in the news soon, once the name of the second patient is released.
So rounding up the 132 passengers is just to show ‘hey, we’re doing something’.
The possible contacts (what did the person do in Cleveland, and/or elsewhere?) and battle to contain the disease had been lost days/weeks ago.