Lumping attempted murder and people saying mean things on the internet into the same bucket is a mistake with far-reaching consequences.
To pick a uncontroversial example: scientists have made all sorts of false claims about food/diet in the last 50 years, and their retracted imperatives have taught people to reject listening to them. Since "scientist" (and "doctor", "professor") are the major terms that people think of, that distrust then spreads across to other fields.
I do think that actual death threats should always be treated as legitimate threats, though.
It's just bullying. We have laws already. Those consequences should apply.
For adults, I guess there's "hostile work environment"?
It's time that we quit thinking that just because something is "online" it isn't harmful.
If anything, threats over the internet should be considered more dangerous as the reach is larger and you are more likely to attract people who are genuinely deranged along with the attendant increased risk of violence.
The fact that we don't prosecute these kinds of online threats is simply because nobody cares about the plebians who don't have enough money to opt out of the problem.