I would definitely expect all of that to be handled by the primary contractor (i.e. the person who specializes in construction sites). No?
Being a contractor doesn't automatically grant someone the right to delegate access to sites and such.
I think a lot of people in this thread have misunderstand what the law is actually saying. The law doesn't say that if you're given contractor status you can do whatever you want. The law says that if the job is misclassified as a contracting position when it should be a full-time position, then the employee is owed benefits and such.
If you sign a contract with a company that says you will not share the code, design docs, system access credentials, physical building access, or other common stipulations, you can't automatically ignore those because you're a contractor.
> I don't see why software projects can't be the same.
Contractors can't automatically give subcontractors access to the plans, the construction site, and so on. The contracting agreement will have provisions about who can access the site, how they get approved, on what terms, and so on. Becoming a construction contractor doesn't give someone carte blanche to invite other people to a site without regard to the terms of the contract.
Likewise, a software contractor can't just decide to share your codebase and design documents with a subcontractor because it almost certainly violates many of the contractual clauses they agreed to.