Some "deniers" aren't "deniers". They're tired of the scare tactic headlines, politics, and fatalistic language.
When you call them "deniers", you push them even further away. You've gone from being mildly annoying to name-calling.
This applies to other subjects as well - masks, LGBT politics, social equality, etc.
Name-calling turns potential allies into entrenched enemies, yet some proponents for change double down on this tactic which further erodes their goal of winning people to their side.
The past 20 years have proven out pretty basic math: when you multiply a bimodal distribution by a constant > 1 you still have two modes but the peaks are farther apart. The deviation is that in our case the peaks are actually higher than before.
They aren't potential allies. They are fully entrenched, and I won't be gaslit into pretending that's my fault. Not will I waste time on the lie that they'll come around if only I suck up to them. I will call them the name they have earned.
This is the same problem the Democratic party has when some fringe members of the party essentially say, "fuck you, vote for me." It poisons the well.
It doesn't matter that the well-meaning people within the party are always on their best behavior and are making every attempt to be inclusive. A few bad eggs ruins the perception of the entire batch.
This is militant and excludes people. It's also really self-serving. You get to feel good about yourself while simultaneously pushing people away.
That's the thing. I'm not a militant left winger. I'm part of the Democratic mainstream that the left wingers call right wing, and they're probably correct. I'd be considered center-right in most European countries. I am very angry at that segment of the left who won't vote for Democrats and instead leave us with literal fascists.
And yet they are still more likely allies than Republican "centrists". They just voted for a felon and an insurrectionist. They knew that he was incompetent, stupid, and deliberately hostile. They voted for him because he's not the Democrat.
I will not be able to change their minds. Any candidate I vote for will always be their enemy. They're not just waiting for a kind word from me to put that hostility behind them and be nice centrist friends.
The Democratic party still has not accepted that. And they will continue to lose.
Deniers will complain about any name you give it.