This is *not* what Mueller found. And this is a misuse of the word "proof." And this is a misuse of the word "collusion." So either @washingtonpost has no one editing its columns, and/or it doesn't know what the Mueller Report said, and/or it doesn't know or care what words mean. 
I'd also note that this columnist is low-key leaning *very* heavily—in his first sentence, see the tweet prior—on the word "hackers." But soliciting computer crimes, aiding/abetting computer crimes, and obstructing justice to help hide computer crimes is after-the-fact collusion.
The columnist's next sentence is better, but comes too late—as he (the columnist) has already wrongly told readers that "collusion" and "conspiracy" are synonymous; that "proof" means "proof beyond a reasonable doubt"; and that you can only collude *before* a crime occurs. False.
My point is that we're now three years into the Trump-Russia investigation and its aftermath and *still* we have no agreed-upon language—even among the editor class at top newspapers—as to how to use the words "proof," "collusion," or "conspiracy." I think that fact is *amazing*.
It's sort-of correct that Mueller *published* no "evidence" of a "before-the-fact conspiracy" between Trump or his team and Russian "hackers," but a) we don't know if anything Mueller sent to the FBI CID was relevant evidence, and b) Trump did *solicit* at least one of the hacks.
The bigger problem is that—as I'll say over and over for however many years I must—*no one was accusing Trump of a before-the-fact hacking conspiracy*. That quite literally *isn't what the Trump-Russia scandal was*. We still don't know why Mueller thought that was his sole focus.
But the columnist's bad faith—or ignorance—is proven in his use of what has become the "respectable" right's oldest bait-and-switch: say "no *conspiracy* with *hackers*" and then immediately pivot—without acknowledging it—to "no *collusion* with *anyone ever*." That happens here.
