In college, we had a digest email that went out to all students. It had things like event announcements and a lost and found section. Every so often, a student posted about a lost/stolen laptop, and no matter how stressed out they sounded, they never directed any anger at the person who stole their computer. They always said, "If you have my computer, I will take it back, no questions asked." At first I didn't understand this at all. If someone stole my computer, I'd be ready to pound them! Why was everyone being so calm? Then it hit me - they weren't necessarily being calm, they were being effective. If they posted how angry they were at the person who stole their computer and what they'd like to do to them, that person would be much less likely to give it back. It's easy enough to lose something small like a cell phone without it being stolen, but a laptop? Not so much. Telling someone you "found" their computer is going to raise suspicion, and really the best way to get it back is to promise not to say or do anything bad to the person who took it. It doesn't mean you don't want to do anything to them, it means you're being effective at getting your computer back.
This is what I'm doing with the validation book I'm writing. The friendly, solution-focused tone does not express how I feel about the people who have invalidated me. It's not the tone they deserve. It doesn't mean that I'm "over" stuff from the past or that I don't plan to tell people directly just how much they've hurt me. It means that I need to hold the reader's interest and I need to get the reader to like me if they're gonna listen. I need to be effective. It doesn't mean that I want to be civilized to someone who stole my computer, it means that I want to get my computer back.