Newsweek is not guilty of libel or defamation because those are torts for which criminal "guilt" is meaningless. Newsweek would not be liable for libel or defamation because being labeled the creator of Bitcoin is generally not something that would harm one's reputation.
Libel or defamation claims are generally applicable where one person claims another person did some heinous act, like rape, or a felony, and told other people about it. Some statements, like accusing another person of rape are considered so "heinous" that to win, all the plaintiff has to do is prove the statement was made, in which case the burden of proof shifts to the defendant, who must now prove the accuracy of the statement. Depending on the nature of what was actually said, the defendant's burden may range from simply proving that their statement was reasonable based on the facts to proving that what they said is verifiably true. (And note: not a criminal case, so: proof on either side simply means more likely than not.)
Nit: you appear to be describing per se defamation (accusations of heinous actions), but this is just a small subset of all defamation claims. So long as damages are incurred, false statements of fact can and do routinely incur liability, turning on the credibility of the statements, the recklessness (or deliberate deceptive intent) with which they're made, &c.
It's definitely not the case that a newsmagazine would be in the clear simply because designing Bitcoin isn't a crime (although other factors probably do rule defamation out).
Libel or defamation claims are generally applicable where one person claims another person did some heinous act, like rape, or a felony, and told other people about it. Some statements, like accusing another person of rape are considered so "heinous" that to win, all the plaintiff has to do is prove the statement was made, in which case the burden of proof shifts to the defendant, who must now prove the accuracy of the statement. Depending on the nature of what was actually said, the defendant's burden may range from simply proving that their statement was reasonable based on the facts to proving that what they said is verifiably true. (And note: not a criminal case, so: proof on either side simply means more likely than not.)