I agree with GMIF here. To respond, I will need to veer off topic but probably no further than we already are.
Artistic gymnastics, particularly floor routines, should be about technicality and expression, which I think we all agree this young girl has both of, in abundance. But art, in any form, is open to interpretation and can not appeal to everybody. Perhaps the main point of art is to stir reaction, of whatever kind. Again, f that is the case, the routine has succeeded. I suspect the audience reaction at the actual competition would have been equally as divided as those here.
Again with the individual video. I have watched it only once, as a result of this post, and I found it powerful and evocative. Not entirely comfortable but very moving. My interpretation, given that a child was specifically chosen to star, is that her being a child is fundamental and therefore entirely appropriate. To assume that children have no experience, understanding or way to express the effects of addiction/mental illness is to disregard the very real effects they can and do face. If the video depicts, as I feel it does, a child's expression of a frightening reality, then I have to say it does it very well. It's not happy, it's not easy, but it is certainly art.
To contradict that, I would also like to point out that modern life, and certainly modern music, does tend to address sides of life we would perhaps prefer our children to have no reference to. Not every child will interpret things the same way. Some kids might just like the tune and the dancing. For example, my own daughter has been repeatedly singing a pop song for the past few months. I have to say, the lyrics and the dancing she is copying have made me cringe a lot and I've even asked her not to repeat it. It wasn't until I overheard her tidying her room and singing it while she did it that I realised that she thought that 'all the right junk in all the right places' was actually a reference to recycling.