Earlier quoted context omitted.
Maybe we need to start teaching people to habitually attach provenance and confidence information to every fact (really: belief) they report, at least as much as practically possible? "Iraq had WMDs in 2000s" != "I strongly believe Iraq had WMDs in 2000s" != "I find it plausible that Iraq might have had WMDs in 2000s" != "According to that UN report, Iraq had WMDs in 2000s" != "According to NYT, which quotes that UN…
I generally speak like this and find it causes problems with others because they view this as a weak form of speech. It makes you appear uncertain, which should be a good thing, but our society seems to value undeserved confidence far above cautious uncertainty.
Once you've set the bar re: certainty for a particular discourse neighborhood, you can just make claims at that level thereafter without feeling dishonest. As long as you're sensitive to cases where others may have joined without enough context to know that you're out on a limb.