No, we can't. A person who knows nothing about the case and believes what they're told to believe without thinking about it would certainly call it murder, but that's not everyone.
For example, what were the injuries? Do you know? Did you try to find out? The injuries would provide evidence of how the death happened, which should be considered extremely relevant. Do the injuries contradict his account of what happened? Do you know what his account of what happened is? If not, why not?
It's easy to make conclusions based on ignorance, which is why many people do it. But not all people. So your statement isn't true. What also shows that your statement isn't true is that the jury, who were probably all not police officers or legal experts, decided it wasn't murder. So "laymen" who saw and heard evidence didn't call it murder.