Because there isn't any proof.

There is also a lot of hatred, but it's not really mainstream, it's the fringe hysterical wingnuts on both sides fanning irrelevant flames daily in some imaginary war of keyboard diarrhea.

There is also a political and journalistic undertaking here to keep this in the news as long as possible, much like the other side did to the Clintons for many years. Keep them under investigation, keep innuendo and conspiracy theories in the news daily in attempt to politically weaponize them on demand. For instance, if the angry left can keep this up into the 2020 election cycle, they can claim he is under investigation by law enforcement and therefore unfit to be president, where there is smoke there is fire, all that innuendo stuff they use to discredit each other like its a game or something.

The long story short is there really isn't much going on, and there won't be, and media will continue to enrich themselves by dividing us into groups and pitting us against each other.

In the long run, it won't work. Americans are far greater than the media wishes to acknowledge. Americans will continue to be strong and support each other, while the fringes take each other part with hateful slogans and impotent gnashing of teeth.