If it is true and clear that the developer tampered with the codebase because of a personal issue with another developer, I am not even sure that is an issue to let HR resolve; I would want that developer fired immediately. Intentionally fucking with the product, or any other sort of company property, is inexcusable in my mind. Tanking the reputation of that developer is putting it nicely.
I was trying to be measured in the language because I don't consider the TechCrunch article to be completely unbiased on the man, but yes, in general I agree. Intentionally sabotaging code should have you out the door on your ass.
Retaliation in response to rejected sexual overtures is one of the basic forms of sexual harassment. It's arguably a quid pro quo situation and absolutely qualifies as the kind of conduct that can lead to a hostile work environment.
