I just realized that you may have misunderstood my point from the beginning. The point was that it according to halacha, it is assur to say something bad about someone else. Since lying is considered a bad thing, by saying that someone else lied, you are saying something bad about them, and it is either lashon hara or motzi shem ra. Even if you want to argue that lying is not objectively bad (I’m not sure how you would do that, but hypothetically if you would), YOU clearly consider it something bad and you stated as much, so it is still loshon hora or motzi shem ra.
My point about lying for shalom was really a side point. I mentioned it because your defense of speaking loshon hara was that you believe in the truth. Bottom line, according to halacha, believing in the truth does not make it muttar to speak loshon hara/motzi shem ra. But I was trying to tell you that in a nice way, which got you sidetracked discussing when you can lie for shalom. Your examples of lying for shalom had nothing to do with the present case, since we are not talking about lying – it is not lying for you to not discuss something.