It says something bad about us as a species if we can only enjoy a conversation when most or all of the participants are making large numbers of errors.
I don't think there's anything wrong with speculation. But if speculation is more interesting than actual knowledge about the same subject then I think there's something wrong with that.
You make a lot of sense...but I'm afraid I must run into the "wrong" category.
The thing is, the topic under question is usually pretty pointless (see "deceased" example above, or my musing about how the first time bread "raised" must have been freaky, or any such thing).
While learning a piece of trivia is _nice_, it's rarely as interesting as the act of speculation. Because I'm not really (all that) interested in the question at hand, I'm teaching myself (and regularly exercising the ability) to NOT KNOW, to DESIRE KNOWLEDGE, and to ACCEPT THAT SOME THINGS ARE BEYOND MY GRASP. It's good to find that somethings ARE in my grasp (answer someone gave about about "deceased" was the first time I've had that question answered!), but I get that lesson a lot in life.
When I wrestle with the "big" questions (What should I do with my life? Am I happy right now? Why did this terrible thing happen to me? Does existence care about me? Why do I care if it does?) some comfort with the unknowable is good. When I'm dealing lesser "big" questions (Am I actually good at this, or am I just faking it and haven't be caught yet? Am I an insensitive ass to people around me? Can I really buckle down and get this project completed? Why the heck do people vote for <INSERT POLITICIAN HERE>?) I likewise want to have experience with both being able get answer as well as NOT being able to get answers.
Learning is awesome. I love it. But I also need to be good at dealing with wanting to know, or dealing with being unable to know. Around me I see too many people of many ages that aren't interested in things they can't easily learn.
I've seen people move from speculating to assuming too often, but I don't see speculation as inherently wrong.