Re: I can only assume that the stalkage etc moved into legal/crime territory
You missed this bit then: "The four just so happened to be involved in labor organizing at the internet goliath"?
While I saw that and have few doubts its played it's part, it is in every way trumped by this part:
"They argued on Monday that a section of the corporation's code of conduct that says Google employees should “speak up if you see something that you think isn’t right” provided ample justification for tracking and scrutinizing their colleagues."
Sorry, but data my employer keeps and retains about me, my work, and pretty well anything else, isn't provided so colleagues who feel morally superior can snoop through it at leisure for whatever ends they feel is morally justifiable.
The division I work for at the bank is popular with some, and unpopular with others (an equal mix of envy and ideological objections), and my colleagues have absolutely no right to track me. If you don't like a legally permissible project the company is pursuing then you need to leave: you don't get to raid my data and use it for your own ideological ends.
Did they leak the data? Who knows. Frankly it doesn't matter. They had no business using it for ideological purposes when that was not the reason for which it was provided to the company or for which it had been retained.
Rights and laws, including the right to privacy and the law regarding data access, apply to everyone, not only to those deemed worthy by those who consider themselves societies morality police. This might not be a popular view, but think it through. I decide I'm morally superior to you so I decide to track you using data supplied to your employer for legitimate aims - I've made all the decisions and you bear all of the consequences, yet I've not actually been permitted or authorized to do any of what I did, I just decided my morals are superior to yours and then did as I pleased. That, in a nutshell, is their defence.