Unfortunately the brand of science is used to promote these models, which is disingenuous. These models aren't like physics models, they are like economic models.
I'm not a fan of the "less scientific" phrasing, but the point of science is to be convincing to even a skeptic. That's why reproducibility (try it yourself in your own lab!), statistical analysis (there's basically no chance this is a coincidence!), control groups (it's not just an endemic property of the lab), random sampling (it's not selection bias) and other things are so important.
In some kinds of inquiry, it becomes difficult or impossible to apply certain standards. It's flat out unethical and immoral to not treat a man's syphilis just to have better quality evidence. So if you're studying syphilis, you need to find other ways to be convincing. It's impossible to have a statistically significant sample of Earths or a control group of Earths, so the bar for convincing is also higher in climate science.
"Less scientific" probably means "doesn't have access to many standard scientific techniques, so stronger evidence in other ways is essential to be convincing".
Sure it is. It evolved from "natural philosophers" showing off their work to each other. People have always been able to convince themselves of things, but scientific rigor is about convincing other people (i.e., being objective).
The point is to be convincing to a rational mind. It's not a persuasion contest, no. The evidence should speak for itself. But it needs to speak to an audience.
Otherwise it would be a self indulgent exercise and not a corporate one.
For instance, I believe that there are fewer experiments that confirm general relativity than there are that confirm quantum mechanics, so does that mean GR is less scientific than QM?
Does this mean GR-skeptics are on firm scientific ground? No, it does not. The evidence for GR is overwhelming. That QM may have even more evidence does not cast doubt on GR. Both GR and QM have overwhelming evidence, and there is no meaningful sense in which one can say that one is less scientific than the other.
> This shuts down the possibility for a reasonable discussion because one party (the activists) is overwhelmingly guilty of acting and arguing in bad faith
No, what shuts down the possibility for reasonable discussion is people discarding 90% of the experiments and measurements, and then claiming that there is no evidence. It's not the activists that are doing this.