Firstly, Netflix must be livid that he left this bit of hot tea for the publisher after all those mils they paid.
Secondly, there's a sinister subtext that Harry must be aware would come out if he paints William as an explosive, physically violent man behind closed doors. Has William done that to Kate? How likely is it that someone prone to violent outbursts would only save that for one single person in their life and be gentle and mild to everyone else?
Thirdly, it doesn't paint H&M in a good light at all if the source of the argument was about Meghan. He was always the smarter of the two and there's no reason to doubt his judgement. He met her in person and was able to form an opinion well away from the press. Considering his own history with his mother and the press, he would have been absolutely stupid to go reading and believing tabloid stories about Meghan.
Harry sounds like a victim of a narcissist and the money making machine in the USA. As someone said, the timing and revelations in the documentary, books etc were absolutely calculated by a team and nothing to do with him anymore. He was a pawn for many companies to make big money and nobody truly cares about what impact that has on his life. He is only 38 with virtually no work experience. He has zero understanding of the publishing and film industries, and they gleefully exploited him in the USA.