This headline is clickbaity over exaggeration. It didn’t “gut protections”. The protections were already pretty terrible so this was more of a clarification. Prior, the court had sort of waffled on what “true threat” meant. This… didn’t really help a great deal but it did clarify that both the reasonable person test and the reckless disregard tests had to be applied. I recommend reading Ken White’s article https://popehat.substack.com/p/supreme-court-clarifies-true-threats. The big takeaway:

So. To the practitioner, or to the internet tough-talker, what does this mean? It means that the law of the land, at least 7-2, is that a threat is only outside the protection of the First Amendment if:

• A reasonable person, familiar with the context, would interpret the threat as a sincere statement of intent to do harm, and
• The speaker was reckless about whether the threat would be taken sincerely — that is, they “consciously disregarded a substantial risk” that it would be taken seriously.

Colorado’s law played pretty loose with the reckless disregard aspect.

All that said, we need a better test, or better criteria to sort between some kid on LoL forums who trash talks and gets some mother in Canada worried (this actually happened) and when a woman reasonably fears for her safety based on persistent stalking.