You seem to still have an impression that “secure” here is somehow related to “security” of the users or their “authority over their own systems”, when in fact

You seem to still have an impression that “secure” here is somehow related to “security” of the users or their “authority over their own systems”, when in fact it only means “securing” the position of the company that gets to control the thing. Even if Microsoft fires everyone tomorrow and closes, Secure Boot key infrastructure and agreements will still cost a lot. Just like patent pools of former industrial giants that don't just disappear. In the same manner, insane DRM schemes are not made to be solid and unbreakable, or because sellers are worried about home copies (made by people who won't buy the product anyway otherwise). DRM is just a convoluted enough mesaure to protect corporations from their fellow corporations who would gladly make the same thing, but more convenient, or cheaper, or more profitable, and ride the “piracy” wave. In the same manner, Google didn't shove HTTPS into everything because it was worried about the users, but because it was worried about other companies with massive traffic spying abilities grabbing the data Google collected for itself. Et cetera, et cetera.