Personal attacks aside, here's the difference. Surfing the internet, playing Solitare, ect ... is done AT YOUR DESK. You are available to drop things, and help someone at a moments notice. People have little or no problem leaving their computer in the middle of a sentence, to help, assist or pick up other dutites.
However, a smoker is outside, away from their job; and 99.9% of the time has this response when asked to do something "I'll be back in a minute, as soon as I finish this cigarette". The world has to stop and wait until the smoker has finished. That's the difference. If I sit at my desk and have a staring contest at my phone, time is wasted; but I'm available immediately.