I see nothing wrong in acknowledging that there are individuals working for TSA who do good things. (TSA sure acknowledges it frequently on its own blog.)

The main criticisms of TSA here are about structure and policy. Even the personal criticisms are more along the lines of "why does TSA allow these individuals to act this way?", which is actually a question about TSA more than the individual.

Acknowledging the kindness of strangers, regardless of who employs them, is always a good thing.