I believe contractor in this sense is more like staff augmentation, e.g. Equifax pays a fee to $COMPANY, who, employs (W2) John Doe to work 40h/wk at Equifax as a "contractor." It's very common in local/state/federal government to have these C2C (company-to-company) contracting arrangements to get around regulatory or legislative limits on government employee pay.
This is actually much more of an issue than someone just holding two W2 jobs, because these "contractors" are almost always billing hours, and if you're billing the same hour to two people that very quickly approaches actual fraud.
I've done this type of work in the past and I agree. It's probably contracting between companies, but the worker is likely an actual W2 employee of the contracting agency.
The catch however, is that this doesn't necessarily absolve Equifax of miscategorizing workers -- this was the subject of the famous Microsoft Permatemp lawsuit. It is possible for a W2 worker of a temping agency to also be considered a common law employee of the contracting corporation. In Vizcaino v Microsoft, the temps were found to be Microsoft employees -- even though they were also w2 employees of third party staffing agencies.
This is actually much more of an issue than someone just holding two W2 jobs, because these "contractors" are almost always billing hours, and if you're billing the same hour to two people that very quickly approaches actual fraud.