It was Hill’s friends who brought the “harassment” to the attention of the committee.
IMO, Hill had been BSing her friends about her close, working relationship with Thomas. Sort of “hometown girl makes good” story. Following Thomas to new job bolsters this BS. Then when Thomas moved on without her, the friends asked, “’Sup wid dat?” To end all the BSing, Hill says “He harassed me” thinking that would end it all.
But then, Thomas gets nominated to SCOTUS, friends ask Hill to say something, she refuses and now the friends go to the committee with the lie she told to cover her “little white lie.”
All the rest is history.
IMHO if it happened today with the same Senate numbers there is 0 chance Thomas would be confirmed. Conservative cancels Black now.