No the entire argument is silly. I could just as easily suggest drug test makes sense in fast food because who knows, someone with a drug addled mind might thing its a good idea to wipe the grill down with drain cleaner before cooking my burger.
No business have the right to do whatever they like and require whatever they want as conditions of employment, but they should not be encouraged to reach into the private lives of employees. Drug testing is intrusive, and costly. Requiring it should be a quick way to make sure your company isn't on any of those 'best places to work lists'
What companies should do is simply check their employees arrive for work in state they can do it effectively and safely in. At your fast food restaurant if the Assistant Manager can't be arsed to walk around and make sure workers don't appear to be to 'high' to do their jobs properly you got bigger problems than anything a drug test is going to uncover.
Someplace like Disney has tonnes of pre-open check lists and radio check-ins etc. If lower management can't spot operator that shows up to work drugged out than once again drug tests are not the answer. I have seen guys come it work with fevers before from flu and back fork lifts into other employees etc. Drug tests don't screen for flu. There is no substitute for a quick 'hello' and occasional walk arounds for employees who operate hazardous equipment or work in conditions that may be dangerous to them or others. Does matter if its a roller coaster or fryer filled with scalding oil! It also does not matter if said employee was 'tripping balls' 7 hours ago, it matters they are sober while on the job!