When is a threat a threat?

http://dailysignal.com/2015/06/02/co...gn=thffacebook

The Supreme Court’s Elonis decision is yet another welcome example of the correct way to interpret a federal criminal statute, and, more importantly, represents a significant safeguard against overcriminalization. The decision does not bar Congress from using a negligence standard (or some other standard) in this category of cases (or any others), but it makes clear that, unless Congress is quite clear as to what a statute requires the government to prove, federal courts should read those laws to demand proof of conscious wrongdoing as an element of a federal criminal offense.

I disagree with the decision. When one utters an intent to inflict harm on another "in interstate commerce" I think the civil court standard of how the message would be viewed by a "reasonable person" should be sufficient. How does one prove the "awareness of some wrongdoing" that the Supreme Court is demanding for a criminal conviction?