There is a balance, though. Just saying, “Source,” and expecting to be spoon fed information from a stranger on the internet is just as bad.
Like, if I was dubious about a claim, I wouldn’t trust the person making the claim to give me unbiased sources, so I research it myself. Trying to be a pedantic ass is a large part of why I’m knowledgeable on so many subjects.
In fact, I’ll only ask for a source if I know they can’t provide one.