The two theythems that aren't Stevonnie are tokens for the PSA's sake (aka they served their purpose and we'll never see
both of them again). The black boy is Craig of the creek and the hoodie kid is Chloe from We Bare Bears (who's oddly the target demographic for this PSA because she's a 10 year old college student).
It's funny because it's true.
Back when I was on tumblr for fun (who has fun anymore amirite?) there was a SU commentary blog that had an anonymous ask him, "HELP my friend who's kin with Jasper saw the new episode where she stole those gem monster gems and my friend is talking about suicide! What do I do?!!?!?!" and he (rightfully) told them, "whoa holy shit don't ask me, there's nothing I can do. Call 911 if your friend is that upset!" because what the fuck is some internet stranger going to do?
That's what she should've done: NOTHING. Becky really fucked herself and her vision up with her desire to please everyone and still couldn't do it 100% in the end. Crazies were crazy before SU and without getting professional help, they're going to keep being crazy after SU. That's an SJW for you: twisting themselves into knots over literal whos' feelings when those literal whos wouldn't do the same for them.