Just asking for proof would have sufficed to prompt a response on the subject matter, it's the examples that make me question your good faith. Alas, I'll take your last sentence at face value.
I must admit I'm not strong on that trivialization position. The "thinking about" part is more what I'm aiming at when I say it actually had an effect (maybe even the intended one).
As for trivialization: not a linguist, so I can't cite sources here. The mechanism I think is called semantic satiation. It's employed for nefarious reasons too, in the form of "buzzword fatigue" or "buzzword burnout" and I'd argue if this wouldn't be effective, it wouldn't be part of political parties' playbooks. Other examples: Apart from holocaust trivialization (which is actually a felony in my country), another attempt to avoid a similar effect that I find interesting is the protection of the symbols of the Red Cross.
I could be convinced to restrict freedom to prevent harm, but doing so just to have a positive impact goes against me on principle. I get the sense that this is a common principle because all of these lists specifically discuss harms, but it may just be an American thing. So I'm going to talk about trivialization, but it's fine with me if you'd rather argue against this paragraph (or ignore me entirely).
The closest I can find to semantic satiation having significant effects beyond the short term is in helping stutterers, where the meaning of the words would be irrelevant. I may not be using the right search terms though.
An important distinction re: political parties is that they are using the relevant meanings. A master git branch, as far as I'm aware, does not refer to someone controlling someone else but is used in the sense of a master recording. In any event, US Republicans talk about CRT and US Democrats talk about fascism, both ad infinitum. Neither side is trying to normalize or trivialize their attack words, so that's a point against 'if it didn't work, it wouldn't be in their playbook'.
When you say 'a goal is achieved', are you trivializing the accomplishment by using a word from sports? When I think someone who leads is doing a good job, am I trivializing lead poisoning?