Probably because they aren't insured to do anything other than their stipulated job and so if one or two had an accident then "you/we" would end up paying a lot more out in compensation.
Is anyone else who can't get in to work getting a shovel and clearing footpaths/roads etc? Not round here they aren't.
Are you at work getting paid? Does your job describtion include trolling on a MTB website? Or do you get your pay docked for time logged surfing and not working?
Or are you like me jobless and so free to troll the net?
Or have you been unable to get in to work yourself? If your company is docking your pay/holidays/making you work the hours missed? If so then maybe it's ok for you to knock other people.
Isn't there a saying about people in glass houses.