Constitutional rights do not extend beyond the borders of the US. I know you know this.
In this case they are protected because said person is IN the USA. Amanda was NOT in the US therefore subject to the laws of whatever country she was in. Now, in your example, had this person said those things while IN the country, thats a different story.
Edit: Having traveled quite a bit overseas I see this all the time. Jackass Americans thinking US laws protect them while in foreign countries. Sorry, Charlie, it doesnt work that way.