That's not really what the term "conspiracy theory" means. It means "a belief that some covert but influential organization is responsible for a circumstance or event". In this case, an unknown company or government agency is the influential organization behind planting this guy as an employee at Tesla to steal data.

Anyways, the actual wording, I think, is "he also wrote computer code to periodically export Tesla’s data off its network and into the hands of third parties" which is vague.

It could mean that he exported the data off of the network and then gave it to third parties (news outlets). It could also just mean that he uploaded the data to an AWS server, or to his Google Drive account.

It certainly doesn't imply that he was hired by an outside agency specifically for this purpose, which is what the original comment was wondering about.