It doesn't take a genius to tell the difference between a hospital building being flattened and a fire in the parking lot. The people actually there knowingly lied, end of story.
A fire in a parking lot + courtyard where there are many, many people encamped because it's a safe refuge in an active warzone? Even if the building is still standing, that could still mean hundreds dead.
Even if you don't imply known malice, you have a major factor - if a bystander is asked a question they very rarely will say "I don't know" or actually just describe what they saw. It's a well-known effect, and why analyzing recordings can be much more effective.
