WTP, that’s a good question. I guess it depends on the context. If someone says “it’s night”, and I bring ample evidence that it is day, I am indeed invalidating his or her opinion, and I don’t feel it is wrong to do so. That doesn’t mean I should use harsh language, but presentation of the facts or evidence does sometimes invalidate an opposing view.
In the CR environment, there are so many absolutes tossed around, so many strident opinions and positions, that I think the more evidence based responses to these, the better.
On the other hand, there are many conversations here which depend on opinion or the opinion of another (a rav, an authority, a teacher or a posek) that aren’t expressed as supported by factual evidence, but rather by philosophy or world view and what logically follows from that world view. In that case, it’s my opinion that the argument against it shouldn’t be “that’s factually wrong”, it should rather be “that’s an opinion I don’t share, and here’s why.”
That’s certainly not how I structured my responses when I started here, but it is how I try to do so now.