You're assuming that the OP doesn't know whether the specific task he set the freelancer to includes the possibility of a lengthy amount of planning and preparation outside the computer, without even referring to any material on the computer, or not.
That's a fairly strong assumption and your subthread here would've gone a lot better if you'd started it by asking whether your assumption is correct or not.
He is quite clearly incapable of making an accurate estimate of the amount of time, planning, and preparation involved, or he wouldn't need to spy on the programmer to assure himself that the programmer was "working". He'd know just from the number of billed hours.
That's a fairly strong assumption and your subthread here would've gone a lot better if you'd started it by asking whether your assumption is correct or not.