the "Let's" part is literally an encouragement. Surely it can be made legal (e.g. by obvious irony). In a case like Elonis v. United States the defense was that

the "Let's" part is literally an encouragement. Surely it can be made legal (e.g. by obvious irony). In a case like Elonis v. United States the defense was that the statements where more of "I have a wish to kill X" instead of "I/you/we/they should kill X".