It’s possible parent comment is referring to factually proven issues, such as climate change, that the right has its own set of propagandistic facts for.
I’d say the any group of people has areas of less factitious basis for their beliefs. But, We all should want to employ truthful factual real, non-propagandistic ideas, eh? Is this controversial?
If we don’t have ground truth, real facts, what can we base anything off of? Our policies will fail, our dollars will be wasted, and division will grow.
One danger with "factually proven issues" is cherry-picking facts or otherwise taking them from context. For example, there might be stats on which a president sucked for most of his term, but in the last few months those stats were decent (or vice versa); and then supporters of the president might shout those last few months' stats from the rooftops, and then do polls that show that supporters know but opponents don't know about those last few months' stats, and gleefully report, "Gosh, well, we're trying to reason with our opponents, but unfortunately they're just so ignorant, what can we do..."
Another danger is people playing with definitions. A third is people claiming things to be "facts" based on cherry-picked studies (and possibly some dubious interpretations thereof).
Progress can be made, but I think it requires a sophisticated approach. Paying attention to all the above dimensions, and probably to the motives of the people involved.
I agree with your approach but, as a generally extremely left leaning individual myself, comments solely using "the right" (or any individual group) as the example make it hard to assign to this kind of thought process alone.
Some regular self doubt "what I think are ground truth facts may need to be requisitioned and revalidated and that isn't just true for one specific group to consider" is a core requirement of trying to hold a fact based viewpoint, just as important as any other part of such an approach.