"Maslouh was last year a 34-year old employee of Randstad, which was contracted by Google to identify potential job candidates and enter their publicly available information—derived from services such as LinkedIn—into gHire, Google’s applicant tracking system."
GDPR defines that it does not apply to individuals for "purely personal or household activity and thus with no connection to a professional or commercial activity."
Now if you check the LinkedIn T&Cs your LinkedIn account is your personal account, e.g. it is not your employers account.
So anyone using their (personal) LinkedIn account in the course of their job (or other professional/commercial activity) is then potentially subject to GDPR.
In the case of Maslouh, based in London, performing work for his employer, Randstad, who themselves were hired to do this work for Google presents a problem with respect to GDPR and his/their "processing" of people's personal data from LinkedIn.
Basically it seems that Maslouh is acting at the very least as a Data Processor (and perhaps likely as a Data Controller himself in which case he must register with UK ICO and pay the annual fee) by retrieving personal data from LinkedIn using his own account and then transferring that personal data into Google's gHire system.
If Maslouh had used a Randstad LinkedIn account to do so then he personally wouldn't be directly affected by GDPR, though Randstad would - however LinkedIn AFAIK do not offer company accounts at all (rather they provide mechanisms for companys to pay for features that specified individuals' accounts can access).
So does Maslouh have a contract in place with Randstad for his to act as a Data Processor for Randstad? Does Randstad have a Data Processor contract in place with Google which indicates that Maslouh is a sub-Data Processor?
I raised this fundamental GDPR-related issue of LinkedIn accounts being personal accounts and the implications for recruitment people (both employees of a company and also "contractors" of recruitment agencies) with the UK ICO when they had a "Future of Recruitment" consultation (last year? 2021?). The published ICO consultation document from memory made a vague passing reference to LinkedIn-related implications not currently considered.