There is nothing offensive about being a service provider. Even a cleaner.

There’s only a difference – to work on people who sometimes say “thank you” or on people who regularly say “what shit you haven’t wiped out in my office, I’ve been shedding coffee for thirty seconds, my job is worth it, and you here the hell knows what you’re doing.”

So, those who use in everyday speech the circulation of "service personnel" usually fall into the second category.