Actually, I think that was a bad example of "public servants". In most towns in NJ, First Responders (fire, rescue, CERT) are volunteers, and aren't being compensated by the government, like your typical government worker. It isn't a government job.
You SHOULD thank them for their service, they're providing them to you for FREE, unlike the police, hospital workers, road department, etc.
Just wondering, do you include trash collectors, water and sewer department, snow plow drivers, tax collectors, teachers, animal control, etc. in that group and thank them for their service as government employees?
I think that's because the word "service" is being used too generic. The level of "service" a municipal worker provides is just a bit different than what "service" a guy on the front line in Iraq provides. This is where we need to make a better distinction.