The video was so repetitively offensive I didn't watch the whole thing, being the snowflake I am. But that doesn't stop me from having an opinion on the matter. Snowflakes are indomitable.
While the approach shown in the video draws attention away from the central issue, some of it might be reasonable under certain circumstances. Think of it as a form of insurance. During a person's lifetime of contact with cops, it might not be uncommon for one or more of the interactions to not go as wished: one of the parties misinterprets the actions of the other. The consequence begins at hurt feelings and escalates. So it is not unreasonable for the civilian to preemptively attempt to minimize the (remote but possible) negative results of the encounter: "My name is so-and-so. I am eight years old. I won't hurt you". After all, we teach our children to look both ways at an intersection, even when the "Walk" light is on. It's insurance against the remote.
Were I a cop and an eight year old tried to defuse the meeting by assuring me that she won't hurt me, I hope I'd respond with kindness. It would be a way to reinforce to the 8 year old that respect for authorities is a good thing, and that her behavior has some influence over the result of the interview. I see that as a net positive, especially the last bit.
The central issue is largely, but not entirely, a structural problem. By definition, structural problems are not resolvable at the individual level. The difficulty is this. We have an entire (and growing) class of people who are now, and have been for generations, invested in victimhood. If they were held strictly responsible for their own behavior(s), the social benefits of victimization would materially reduce and possibly disappear entirely. On the other hand, the more their problems are perceived as the responsibility of others, the greater their social benefits accrue (of all kinds, including set-asides and discriminatory hiring). When the government has a thumb on the scale, the incentives lay with the thumb. No longer is victimhood shameful. We, as a society, have made it lucrative and resistant to change.
There is, to my mind, no way individual cops can alter the victim mentality of an entire class of people. This problem rightfully goes into the "Too Hard" box.