Because there's sufficient evidence to impeach and indict. Notice it's already determined that Trump sexually assaulted Carroll and then slandered her, denying he committed the crime. Notice it's already determined that Trump committed bank fraud. He's still got some trials to go. The reason we don't see Joe Biden indicted is, there's no evidence. Same reason Comer is pessimistic about his impeachment scheme. Even many republicans are unwilling to vote for impeachment without some evidence of a crime.
Republicans had a majority in the Senate. So he got a pass. But the evidence remains for historians to evaluate. It hardly matters, now.
He was charged with slandering Carroll by saying she was lying about his sexual assault on her.
Jury finds Donald Trump liable for sexual abuse and defamation in E. Jean Carroll case
A Manhattan federal jury found that Donald Trump sexually abused E. Jean Carroll in a luxury department store dressing room in the spring of 1996 and awarded her $5 million for battery and defamation.
www.cnn.com
Jury found him liable for that slander. And when he lost and slandered him again, they found him liable again. That time, for $83 million.
Actually, Trump was accused of sexual abuse by one of his pal Epstein's victims, but it never went to court. It's telling that Trump rewarded the prosecutor who let Epstein off with a slap on the wrist by making him Labor Secretary. But we can't prove he actually sexually abused minors. It's all circumstantial evidence.