Shady dealings such as? (I'm genuinely curious. Not American, and I found it difficult to follow that story when it broke.)

They are referring to the fact that Assange coordinated with Russian state actors to hack the DNC during the 2016 US presidential election. You can find more about it in the Mueller report and the Senate Select Committee on Intelligence report.

https://www.intelligence.senate.gov/publications/report-sele...

I have not read the leaks myself but as far as I know it was about sabotaging Sanders' campaign.

As despicable as this was, it was all the DNC, not Clinton or her campaign. The irrational Republican hatred of Hillary Clinton is absolutely ridiculous and without remotely resembling anything rational or honest. It was a campaign of bullying, hatred and sexism, and ignorance won. The character assassination of Hillary Clinton, the election of President Trump, and the January 6 Insurrection, all stand to embarrass our nation on the international stage. The World turns it's lonely eyes to America, for inspiration, as a roll model, and we just screwed the pooch. If America was a conscious entity, it'd wish it could just curl up and die of embarrassment for the Republican shenanigans over the last 6-7 years. If everyone would simply ignore all other distractions and vote in their personal economic interests, we'd never see another Republican elected to any office, and our economy would boom like we've never seen. But the ignorance and hatred is strong, so our economy will struggle while the uber rich continue to desperately consolidate the vast majority of the wealth into the hands of the minuscule few.

Starting with an assumption that Republicans have a goal of winning elections isn't it pretty rational for them for do character assassination and not irrational? The average voter isn't going to fact check your attack ads.

The republican committees spent YEARS and 10s of millions of dollars trying to get something solid and failed miserably beyond painting her as the average democrat politician. I found it both sad and hilarious.