Yes, but the legal system does not act on the whims of mass adoption. It’s like that mom in Florida who got slapped with terrorism charges for telling blue cross blue shield the deny, defend, depose line over the phone. The harsh crimes are there to chill anyone who might step out of line.
“You people are next” is a threat based on your own position of power. A politician saying that, yeah that’s a threat. Some random person saying it someone else, not so much.
If someone has a recording of an ex saying that to them over the phone, the best you’re getting is a restraining order, if you get anything at all.
Maybe if she said “I’m coming for you next”, then that would have more weight. But now we’re in hypothetical land, so who cares.