Let's remember what Starr's mandate really was: as a political attack dog to find ANY attacks on Clinton.
First, the Republicans looked for the most partisan attack dog they could find, and set him loose to find attacks on Clinton. He spend the money, did the searches, and found nothing, and said so.
So, the Republicans just repeated the process, the next time picking Starr and making his job clear to him. Find attacks.
IIRC, it was an environment where Richard Mellon Scaife put up a $50 million fun to pay for 'dirt' on Clinton. So 'investigators' could travel the back swamps of Arkansas offering people cash to say they saw Clinton sell cocaine, or whatever.
There was a whole army that called themselves the elves, of private lawyers who tried to assist with attacks on Clinton - they are the ones who got wind of Linda Tripp and persuaded her to betray Monica Lewinski. Ya, Clinton behaved badly. It wasn't impeachable, and justice was done when the abuse of power impeachment backfired on Republicans - and cost them their own new Speaker of the House when HIS actions were uncovered.