Yet he didn't rob it.
Arbery went there multiple times, all on film, and never left with anything. Perhaps, he was really curious in the building process. But, other people on video took things.
The owner of the property in question said on the stand that he had several people on video going through the construction site. He reported nothing stolen and never called the police to report any thefts.
Maybe he kept going back to see if anything of value had been left there since the last time he'd trespassed.