I think it boils down to the fact that H&M are always foisted down people's throats as if they are already incredibly talented and the public must adore and consume whatever they create. It's the insidious "being told what to do" and "being told what to like" that is annoying. Based on pure meritocracy, they would never have achieved close to the opportunities they received. The documentary is obviously trending despite not being in the top 10 because Harry is buddies with Netflix and they're featuring it on the front page in hopes more people will watch it. There are probably tons of incredible documentaries buried deep inside Netflix whose producers will never receive that type of treatment.
Some other examples:
Invictus Games receives sweeping BBC coverage in the UK because it's Harry's project.
Invictus is not being broadcast on a single German TV channel, not even the opening show. They are giving tickets out for free in hopes of filing the stadium.
Instead of the opening ceremony, German TV is showing a German-made 45mins documentary about their own soldiers preparing for the Games. There is no mention of Prince Harry or any attempt to keep him in the spotlight.
Harry's main TV appearance is on a sports talk show at 11pm. It's an established show but the timing cannot be a coincidence. German TV execs seem to be determined not to participate in the personality cult of H&M
Holding an event celebrating war heroes in Europe is controversial to begin with, especially in Germany. The decision to accept it was possibly diplomatic and there was never an desire to promote Invictus to the general public.
Being such a tricky topic, it would be impossible to expect viral viewing figures on Netflix. It was clearly going to be "flop" in terms of absolute views from the beginning.