In case of a sustained growth of a company (think Apple over the past 20 years) what the shareholders gain comes from the earnings of the company. Apple shareholders have gained trillions in the past years - no one has lost an equivalent amount.
According to Linkedin there are 25 HR employees at his company Octopus Energy. Their roles are Learning & Development, Talent Acquisition, Onboarding, Payroll Management. These are all roles that are typically taken on by the HR department.
He has an HR department whether he calls it like that or not.
In case of a sustained growth of a company (think Apple over the past 20 years) what the shareholders gain comes from the earnings of the company. Apple shareholders have gained trillions in the past years - no one has lost an equivalent amount.