No, that's completely different. Pointing an unloaded gun at someone is 1) a threat, because they might not know it's unloaded, 2) a violation of established rules and norms about firearm safety, which exist because 3) the gun may be loaded even if you believe it isn't, this is a fairly common cause of accidents.

What we're talking about with a Death Note is something so implausible that it could cause harm that no reasonable person would expect it to work. There's an enormous difference between "I thought the gun wasn't loaded but it was," and, "I thought magic wasn't real but it was.

I agree with someone in this thread who said you don't just get one freebie, but at least three. If I were on a jury and the prosecutor wanted to convince me that the defense knowingly killed people by writing names in a notebook, I imagine there is some finite number that would convince me, not only that it works, but that a reasonable person would expect it to work at the time they wrote the name - but that number might be like a dozen. It certainly wouldn't be one.