(Yes, I understand why some people would have liked to respond to a certain post but, let's not feed the trolls.) Instead, let's get this discussion back on track by taking it in a new direction. I think there have been some good points on both sides of this discussion. However, I come down in a slightly different place. I think Harry has a weakness; well more than one, but in this case he has an inability to see himself as others see him. OK, doing that is a difficult thing for many people; maybe most people, to do. However, in this case Harry has had many, many clues; which if he had paid attention to them, might have allowed him to be proactive and at least attempt to get ahead of the problem he had with Ramirez and company in Peace Talks. (I know, it's confusing so far, just go with me a little further and it should become clear or somewhat clear.)
What are the clues Harry has been ignoring or not paying enough attention to? Look at the constant pattern of suspicion Harry has faced since he seemingly returned from the dead as the new Winter Knight. Sarissa didn't trust him. Bob didn't trust him. Murphy didn't fully trust him; at least not initially. Fix didn't trust him. Lily didn't trust him; again, at least not at first. Butters didn't trust Harry's story about being being dead and later he didn't trust Harry at all. With the exception of Lily who was more worried about the possible infection from Nemesis, the rest of those characters were afraid that Mab had changed Harry for the worse. However, it doesn't end there. Harry knows that whenever he is seen with Thomas or Lara Raith, it's not a good look. The reputation of the White Court of vampires brings some taint to whoever would willingly associate with them. Most people would have realized they had a problem and needed to become proactive in addressing it, but not Harry. He shouldn't have been surprised that at least some of the younger wardens might be concerned, and might even be worried that he was no longer the Harry Dresden they used to know.
Michael, Molly and Thomas are the only people who didn't automatically think "Harry may be a monster or becoming a monster" when he returned. However, Molly's judgement was warped before she became one of the fae (mostly by being around Lea) and Thomas notices a new predatory behavior being demonstrated by Harry; but Thomas thinks of himself as a monster, so he doesn't make any negative judgements about Harry. Thomas just warns Harry that he needs to learn to control what's going on inside of him. Of course, Michael doesn't prejudge Harry because he's Michael, but also because Harry came to him looking for help. Oh yea, there's Mac, but is Mac really human?
I've actually thought through why Harry lacks this self-awareness, but why go there. I'm not sure how deeply Jim thought it through when he created Harry. In any case, I think Harry had exactly one opportunity to attempt to reach out to Carlos Ramirez before everything went to hell. That opportunity was right at the beginning of the novel when Warden Ramirez showed up on the beach where Harry and Thomas were running together. (Caveat, I haven't reread Peace Talks or Battle Ground. To be honest, as time passes the less I like either of them, though there are parts of them I like.)
Harry notices that Carlos is paying attention to the ridiculous amount of weight he is working out with. That was the time for Harry to (attempt) to reassure an old friend that he was still the same person, more or less. Once it was demonstrated to Harry; by the road block and tracking devise, that even his old friends no longer trusted him, Harry wasn't going to meet them halfway or compromise with them in any way. It's not in Harry's nature to react well to threats. As far as being associated with the White Court, it would have also been a good idea if Harry had come up with a good reason why he should be seen with Thomas by a member of the White Council. He's had plenty of time to realize that might be a good idea, but Harry isn't very good at lying, so he hasn't even tried to think of a good excuse.
At the scene on the beach, I don't think it would have been unreasonable for Harry to say something along these lines: "Carlos, I know you must be wondering if I'm still the same person I used to be. I've had a lot of people who have been worried about exactly the same thing." I don't know what Harry would have said after that, other than it would have had to have been very short, and probably included a promise to sit down and talk in more detail later. Would such a statement made a difference? I don't know, but at least Harry wouldn't have come off as clueless as he did when the Wardens stopped him after his meeting with Lara.
As far the White Court issue goes, that is a much more problematic issue for Harry to deal with. I suppose Harry could have said something like, "Baron Marcone, the White Court and a group of vigilantes have created a temporary alliance against the Fomor here in Chicago. (Implying Harry is the primary vigilante in question.) Sometimes this requires discussions and negotiations between allies." While it wouldn't have been a lie, it's way more devious than Harry usually is with friends. So even though I think it would have been a good idea, it would have been out of character for Harry to do this. I suppose Harry might have told Carlos that Captain Luccio knows why he meets with Thomas Raith, but that would have become very complicated, very quickly. Harry might have had to give Ramirez a letter to take to Luccio to confirm what he said was true and hope Captain Luccio wouldn't decide that now was a good time to be concerned enough to reveal the entire truth to Ramirez and the rest of the White Council.
I think Harry had one other opportunity to reach out to Ramirez. I've written about this idea before in another thread. After Warden Ramirez read Harry the demands from the White Council and Harry responded, there might have been an opportunity for Harry to reach out to Carlos as an individual. Harry might said something like this: "Warden Ramirez! You wanted to know about secrets I've been keeping. OK then, come closer and put a veil or other spell over us so no one else can hear this. Remember how I exposed Wizard Peabody as a traitor at Morgan's trial? There's something I didn't tell the White Council at that trial. Peabody wasn't alone when he attacked the Senior Council members on that island and killed at least one warden. I know that for a fact. But no, I don't know who the other person is, but there is another traitor on the White Council. Now ask yourself, who on the Council are you going to report this information to? Because, if you tell the wrong person you may be signing your own death warrant. Watch your back. And that is the least dangerous secret I know." Perhaps telling Ramirez something like that might pay future dividends. Of course, that assumes Ramirez would believe anything Harry said at that point.