HR roles, like most others, are numbers driven. Recruiters are expected to deliver a number of applicants, interview a number of candidates, etc. This means that yes, they often interview people they have no intention to hire: It makes the HR person look good.

This can happen if they have a diversity hire directive but interview non-diverse candidates, but it can also happen if they want to hire a white guy but have a company directive to interview diverse candidates for every role. Either way, they can say they looked at everyone before hiring whatever candidate they wanted.