The reason doubt appears to help you (when you have no real information at all), is that every
statement of truth tends to have flaws. In politics the flaws are usually huge and glaring, but because both sides have their interests in the political outcome, both engage in half-truths, thus each leaving themselves open to arguments proving them wrong. Here's an example analysis along these lines:
https://firstlook.org/theintercept/...s-media-still-cant-get-iraqi-wmd-story-right/ (I don't particularly agree or disagree with the opinion presented, but it's a good example of trying to figure out what the real truth is.)
That said, "doubt", per se, is NOT helping you, especially if you take "doubt' as meaning likely 100% false. What you are looking for is called "discernment", not "doubt". Discernment requires actually researching something (much easier now with the internet) on your own, allowing yourself to develop an informed opinion that isn't based on what people say, but on the overall patterns of what they're talking about.
Here's an example of my personal opinion/discernment w/r to the 2nd invasion of Iraq. The problem in my mind is not whether Saddam deserved to be invaded and toppled. There are lots of reasons beyond WMDs that he "deserved" it, especially multiple violations of the no-fly zone and firing on US aircraft, any of which could be considered an act of war. Or if you want the moral argument, he was an evil dictator who, along with his sons, abused his people. But that's all irrelevant to the question of whether the war was a good idea in the first place. The problem is that the goal was to essentially turn Iraq into a client state. They called it "freeing Iraq" and probably had visions of Iraq existing as a free state completely independent of the US, but there was no way that could happen without a huge ongoing US military presence, and there was no way a huge military presence could be guaranteed for the decades necessary to stabilize things. Keeping troops in Germany, where no fighting has occurred since WW2, is politically easy. Keeping troops in Iraq, with ongoing incursions especially from Iran and various terrorist groups, is extremely politically difficult. That puts the US in a lose/lose situation: either stay and put up with soldiers getting killed but otherwise keeping the peace and protecting the Iraqi people, or leave and let the country devolve back into another autocratic state of some kind.
So whether you buy my argument on this point or not, my big-picture point is that the "truth" of whether WMDs were really at stake is a non-issue. It could be true, and the invasion would still be a bad idea, or it could be false, in which case it was one out of 19-or-so cited reasons for the invasion that happened to be false. It's the matador's red cape, the reason that had political legs, and nothing more.