Earlier quoted context omitted.
From the perspective of a technologist it's clumsy and imprecise language, but it's not wrong. He wrote code that was explicitly designed to bypass the company's security and treacherously act in a way that caused damage to the company's interests, then he inserted it using other people's security credentials. The only elements missing between what he did and what a "real" hacker might have done is breach a technical…
I don't begrudge Tesla for portraying facts as damning as possible to the opposing party -- that's what any litigant would do (and should do, I would think, although IANAL), as long as no deliberately false statements are made. So "technically true" is fine by me. But since their investigation is still ongoing, and they haven't felt the need to divulge more specific and damning assertions, then it's fair to consider…
As to your last sentence, I think it would be difficult to argue that automated and ongoing bulk data exports could ever fit with any definition of whistle-blowing. If he had legitimate concerns, and evidence of those concerns existed in electronic form, he could have simply walked the specific evidence out of the building on a thumb drive.
That being said, we don't know exactly what data was exported, so any speculation (including my own) is rather pointless...