So why would you deny me the right to hold several part time contracts instead of a full time "job"? I'm not in those industries.

It is not about denying but showcasing that it might not be as beneficial as you somehow believe.

I'm speaking for myself. I like having several part time contracts more than one full time job.

Of course, that only goes for IT if done remotely.

That's no reason to throw seasonal warehouse jobs at me as a counterexample.

because the overhead of a PT or fractional employee is just about as much as a FT one, and why should I give you 100% attention when you only want to give me 50%?