The disparaging remark was about his name being a title vice a name. Your screen name is St Johns - if someone said you can name yourself saint, but you can't BE a saint, that would be disparaging towards you.
But, as usual, you are trying to distract from the larger point - Barron Trump is just a kid who's last name happens to be Trump, so the witness felt she could use his name to try to attack President Trump. In comparison, Greta puts herself out there in the public domain, attempting to scold large swaths of the world for not doing what she thinks is right. Now, most of us do the same thing at our local watering holes, not in front of the UN. Most of us are aware that we can be responded to by those in our local watering holes if we do that, just like Greta can be by those to whom she was speaking (the whole world). Barron is in his room doing his homework, and gets his name ridiculed by a Democrat witness.
You can distract all you want, but it doesn't take away that basic difference that makes your "point" of conflating the two completely invalid.
What was the attack, specifically? That she's angry? That's not an attack against someone who SCREAMS that she's angry at the whole world for not acting in the way she wants them to.
If she were making anyone angry, they'd probably say so. Pretty much people just feel sorry for her for being used.