I know he can sue. My point isn't that it's illegal, my point is that I don't like it. I also don't like it when newspapers do exactly the same thing, accuse people of crimes before they have been convicted.
It appears he just says that this guy has his MacBook, not that he stole it. He says his MacBook was stolen and this guy has it. But doesn't say that this guy stole it.
The caption on the photo at the bottom of the page (presumably the first picture chronologically) says "Guy driving away with my MacBook." Combined with the assertion that the laptop is stolen, it's hard to read this as anything other than an accusation of theft.
Is it possible to be convicted for a crime without being accused? Someone is accusing you of committing a crime- the plaintiff, in court. Isn't that all he's doing?