As expected they are going on the attack and for that purpose lies are the norm. The first case is clear - he had a sexual relationship with a Prostitute, That is normally the first "discovery" of the Democrats when somebody do not submit to their wiashes. The second reason is that Johnson does not have assets - normal with people who ail enrich themselves through insider trading and backhanders to help people getting past laws passed by the House or Senate. Johnson is a criminal - he dares to live from his salary earned as a House member and now Speaker.
They lied in the House about an alleged loan one of the Committee chair got from his brother - obviously the alleged loans Biden gave his family and they then once they get backhanders from the Chinese, Iran or other corrupt countries they repay Biden the loans he made to them. It was an obvious lie. The said chairman apparently bought a farm from his brother and paid him the full purchase price for the farm - owing him nothing. And there was a row in the House when the Democrat who came up with that story were told to his face that he is a liar an he could produce no evidence on the issue - he claimed he read it in the newspapers as if that is a prove odf anything.
It is like Garland said when questioned about why he instructed the FBI to act against parents attending school board meetings. When asked for evidence to substantiate the violence claims - Garland said he read some newspaper stories about such violence. He obviously could not produce any evidence of violence at such meetings and could not produce the alleged newspape reports. The worm was squiming when he came up with that allegation.