Whether it fits any legal definition of a death threat or not is... kind of moot, you can be a dick to someone else without violating the law. Society isn't built on laws, but on decency and respect, and wishing anything negative on someone else isn't it. A few days ago the CoC of an online community was posted, and "slow death" threats wouldn't pass their "be kind" rules either (https://www.improbableisland.com/coc.php, via https://news.ycombinator.com/item?id=39135779).