Because stating observations, whether true or not, isn't always an effective way forward. I was working under the assumption that the response was intended for the original commenter, which may have been assuming too much, but when it can be summarized neatly as "You're wrong. Your whole way of looking at this is wrong. Everyone else is right, and you need to just accept it." but with different words, I think it's not effective at engaging with that person. I think that the recipient of that might feel less inclined to accept an alternative point of view if that's how the interaction starts.

There is no effective way forward with someone who insists that they're unwilling to be persuaded.

I don't think that's what we have here. We have someone that's not persuaded by what they've seen. Has anyone asked why? Even if someone is wrong, that doesn't mean they don't have something important to contribute.

I'm just sad the the first response wasn't something along the lines of: "Why? What does the graphic being a cartoon have to do with how accurate the data and the point it's trying to express is? Why are your experiences in a specific region supposed to map directly towards the overall global scenario? Why are you using hottest days in summer in your observation instead of total hot days, which is actually what's being discussed, since it's possible for the average to be much hotter, even if the largest outlier isn't as high for that year, right?"

Ars longa, vita brevis

It is not the responsibility of sensible people to persuade every last person in existence of the wisdom of a course of action; that's a recipe for paralysis.

What we have here is someone who expressed an aggressively ignorant counterfactual position and rebuffed polite encouragement to consult primary sources. Perhaps the person is trolling, perhaps they're just a fool, but either way people who make objections in bad faith do little other than waste time, and making endless excuses for them is a further waste of time.

This is why I said elsewhere on the thread that it's time to just move on without the buy-in of that part of the population that rejects the reality principle.