It's not about the complexity, it's the cost and risk exposure. Employees come with costs (workers comp being the big one) and risk exposure that 1099 workers do not have (and what the employer gets in the trade-off is more direct control). For someone doing menial work and getting industry experience on the side (most trades have entry level jobs like this) that additional cost/risk could be the difference between their position existing and just tacking the responsibility onto some other existing employee.