I think a lot of us only roughly remember the details (or didn't follow the later revelations) about Assange. My memory was weak, too, so here is a short refresher (with links!)
Pre 2015
Wikileaks did ethical releases of leaked information (vouched; cleaned of names and details that would expose individuals to danger) and exposed generally diplomatic and military-industrial dirt.
Trump Campaign
Assange and thus Wikileaks sided with the GOP. Wikileaks had a line to Trump's campaign team. They also sat on a trove of DNC E-Mails provided by Russian hackers. Wikileaks timed releases to blot out news that could hurt Trump. In one case, the Trump campaign urgently asked for a leak and got Wikileaks to act within 30 minutes. Wikileaks also refused to publish leaks harming Russia.
From the private chat logs (more in the Business Insider article linekd above), some things Assange said to his, until then, progressive aides
Assange: "We believe it would be much better for GOP to win. Dems+Media+liberals woudl [sic] then form a block to reign in their worst qualities."
Assange: "Russia is absolutely terrified. Kalingrad, Crimea, and its only foreign naval base, Syria are all under threat and are not protected by Russia’s strategic depth. Meanwhile the US hacks the hell out of it"
It looks to me like Assange got suckered in by Russian propaganda rather than sell out intentionally, but that's just my own guess.
Rape Charges
In Sweden, he used his fame to obtain sex from two women, both times trying to refuse condoms. He was creepy and pushy with both. Woman A suspected he manipulated his condom. Woman B woke up in the night to find Assange had climbed on top of her for "second servings" without asking and had penetrated her without a condom.
It gets too messy from there. The US had an interest in Assange's extradition and may have plausibly exerted pressure. The women received threats and hate. Russia fanned the flames under everything to fuel division and turn more Wikileaks supporters against the US.
The rest is history. I don't know where to stand. Assange and Wikileaks were once forces for good. But, in my opinion, he got played, never realized or never admitted to it, and is now just another lackey aiding Russia.
I think we can separate the question of whether he ended up working for Russia from the question of how to treat him fairly. If we would want a certain level of humane treatment for a journalist publishing leaked information, that should apply whether or not we approve of the agenda behind what they're doing, and whether or not we think they're being played.