Arguably the initial post was meant to convey confidence and authority on the subject. When questioned you could either dive deeper and explain in more detail why x because of y (if so inclined), ignore it, or... do what they did.

No one owes anyone anything, but if you want to represent something; answering the question more in detail would have either closed the issue or raised more scrutiny, both of which are a good thing when trying to figure something out.

I don't have to trust someone to check their research and look at how they worked. If the work doesn't pass muster, likely the results don't either. Again, you can view it as entitlement, but if you're not going to bother backing up your claim, why make the claim to start with?