It all hinges on the existence of underlying criminal acts. But even the linked article offers several paragraphs which refute any equivalence between whatever Ukraine or its operatives did and provided to the Clinton campaign unsolicited -- and the Russian psy-war campaign and profoundly numerous contacts with the Trump campaign.
Here's an aspect I've mentioned before. There had been no further mention of it since late 2015 when I e-mailed the White House inquiring about more details. there were two major "school-terror" hoaxes, very similar in nature and timed (or scheduled) to occur within 48 hours prior to a major GOP debate and then a Democratic town hall. The two largest urban school districts in the country -- LAUSD and NYC schools -- were targeted with e-mails threatening a major attack to blow up the kids. Real muslim radical terrorists would not just create a hoax: they would have literally blown up the kids. But the attacks provided a sounding-board theme to Trump in the debate, to which other GOP hopefuls offered their own knee-jerk responses. It would also allow a contrast with the Dem oppositions response.
FBI later explained that the origins of the threats were IP addresses in "eastern" Germany. If Putin's psy-war campaign was behind those hoaxes, then millions of parents and their children in predominately Blue voting districts were terrorized. It was definitely terror; it just didn't follow up with the violence.
And if those acts, illegal that they were, were used to influence the campaign, then Trump benefited from it.
Was Trump behind it? Who knows? But there are all sorts of possible aspects of criminal responsibility to the other aspects of the Russian psy-war campaign that could (and do!) haunt elements of the Trump campaign and Trump himself. One only needs to prove foreknowledge to charge Trump with misprision of Treason or misprision of a felony -- which are both criminal and impeachable.
On the other side of those facts that might lead to proof of collusion and treasonous collaboration, there are Trump's own acts which seem to consistently support Russian agendas as a geopolitical adversary of the US. Trump has gutted the state department as a tool of American influence throughout the world. He has promoted distrust of our national security apparatus -- damning the messengers who brought news of the Russian campaign. He has damaged our relationship with NATO and other allies.
The list goes on. Basically, Trump is playing along with the most logical elements of a Russian agenda to damage US influence around the world.
In comparison, Ukraine has a pittance of resources to do anything similar, and whatever their agenda, it is simply to obtain American support in their conflict against the Russians.