I like Kotaku for the most part. I think folks like Stephen and Jason are great people and I love reading their pieces, but on the same token, I'm looking at this both ways and playing devil's advocate for the sake of it. Going ahead and publishing excerpts from a script of a project still in development, or spoiling a stage announcement a half hour or a few days before its going be announced, are legitimate reasons to be fairly upset in my opinion.
There is another type of leak, however. These are leaks where they're informing the consumer about practices or subversion a group of people are trying to get away with.
If Bethesda comes out & lies to consumers that Arkane is not working on Prey 2, when that is in-fact what they are doing, then I do think you can and should run that story. You're setting the record straight for the consumer. Running a story about how the OS for a console is actually not working properly behind the scenes, or how the internal machinations of how a publisher feels for its consumers is something you should report on. Or hell, reporting on negative business practices that go on is perfectly fine. That should be encouraged.
These blacklists don't seem to arise from any sort of story of ethical or moral violations from Bethesda or Ubisoft though. Has Bungie blacklisted them for running that article a month ago about how difficult stuff was/has been on Destiny? From what I know Bungie likes Kotaku, or at least Jason. Did EA blacklist them for continuously running stories on the poor release state some of their games were in in recent years, or how bad the work conditions have been within EA studios at times? No, they haven't. Did Sony around the time of the PS4 unveil? No.
From devs that I've talked to, there is a reason why publishers and developers want secrecy around their projects - when they show something/anything to the public, those things BECOME promises, even if its still in development, even if its non-final, even if its early. They have to deliver after that point. And its been something that has bitten quite a few devs in the ass in the past.
So yes, devs have certainly become more reclusive, but with admittedly good reason. Their dev times have become way, way longer, which makes the spoiling of surprises even more of punch to the face than many realize. It's one thing for an insider to go on a forum and say a few details on a game or say someone they know that knows this one thing is in development said a thing, and entirely another when you are showing excerpts from a leaked script, or gameplay footage/assets of a game that doesn't even exist yet. Trust me, I WISH publishers and studios were more transparent in their development process more than anyone. 100%. But I also at least see where they're coming from as well.
That's my two cents anyway...