There's no "trick" about it. That's literally the way business has always worked since the first private companies were established.
This forced firms to then hire third party vendors who in turn 1099ed the "workers" to work at company X, including google.
Should we force every company to be vertically integrated and directly employ everyone who works at one of their facilities? It's just a ridiculous complaint.
Now, if they took the entire recruiting work for that team and gave it to the outsourcing agency who did the job from their Florida office, it wouldn't be a problem. They could also do what Apple does and host all the contractors in a separate building with no contact with Apple employees https://www.bloomberg.com/news/features/2019-02-11/apple-bla... but the optics of that isn't great either.