So if someone does nasty things, but getting access to evidence for these nasty things is impossible without breaking a law, how do you suggest that one should go about proving that the aforementioned nasty things were committed?
Pedophiles do nasty things on the Internet. Uncovering pedophiles on the Internet is impossible without mass surveillance of the Internet. How do you suggest that one should go about proving that someone is a pedophile?
In both the case of pedophiles and state actors who are breaking the law, the answer is the same. Wait for them to slip up. It's hard to keep something secret forever.
That's sort of the point. When someone justifies an action because it's "impossible" to stop bad thing X without doing morally questionable thing Y, be skeptical.
Not sure. You might have to take one for the team like with other acts of civil disobedience.
That said, in this case, were nasty things uncovered? I can't find anything about that. Also, mixing investigative journalism with theft and use of other people's credit card numbers is probably not the best way to maintain an appearance of innocence.