I mean, the roofer is likely a employee of a roofing company. You pay 1 check to the roofing company, and they do payroll for the roofers. Not many people hire 10 roofers 1 by 1.
Coder is a better question. I think the argument is that they have a lot more freedom in what they do... i.e. pick their own libraries etc.
Google "Vizcaino v. Microsoft". Whether or not a coder is a contractor or an employee depends very much on the level of control they have over how, when and where they do the work.
> I will say my only understanding of 1099 vs employee has always been "Does the worker have a set schedule" If the answer was yes, they are a employee- If no, a contractor.
Fast food workers, retail workers and such? They're hourly employees, but employees nonetheless.
