If I look at the various projects Netflix spends its money on I have a hard time believing that their programming strategy is fundamentally based on a thorough analysis of data.
Still, could be worse.
I think what you have a hard time believing is that a majority of Netflix users have different tastes than your own or the corners of the internet you frequent.
I can shit on Fuller House all day, but I recognize many people must be watching Full House on Netflix for it to exist. Death Note? Not so surprised. It's one of the most acclaimed anime series of all time, and one of the most widely discussed, even years later.