It is a balancing act, to be sure. Of course, for every "Einstein", there's a hundred crackpots with perpetual motion machines who think they're the next Einstein.

The problem with conspiracies is that those proposing them tend to have no much investment, emotional or otherwise in them. In many cases, it's not a genuine quest for truth any more. Me, if conclusive proof came out tomorrow that JFK was killed by Oswald alone, I'd have absolutely no problem with that. That, to me, is what skepticism is about: coming to conclusions based on the evidence, not what you want to be true, or because there was a document 50 years ago which suggested something kinda similar coughOperationNorthwoodscough.

The other problem is conspiracists' reluctance to come up with an testable alternative hypothesis. We have a who, how and why for 9/11. It may not fit all the facts perfectly, but if you want me to change my mind, you need to come up with a who, how and why that fits the observed facts better. Highlighting eye-witness reports of molten steel is otherwise no more than slightly interesting.

Edit: the mistake you pointed out can happen to anyone including a skeptic. How would ppl read newspapers?

As with all data: taking into account the reliability of the source, based on its past record. If the information they have provided previously has been accurately reported, then you put more credence in it. If it's a source with no track-record, which has demonstrated a clear agenda that skews its reporting (hello, ENE News!) or one which has previously been guilty of misreporting, you're more cautious. I've seen enough faked photos before to know not to believe them, even if they're confirming a deeply-held belief - in this case, "Reddit is corrupt". And again, if someone then shows up bringing additional information, I thank them, rather than lashing out. That's what seeking the truth is about.