Do you want the operating system to prevent an app to read/manipulate the pixels of a raster image submitted to it? No, thanks. I would avoid instead any app that forces me into doing something that I don't want to do. Detecting screenshots is just one of the many abusive behaviours that most users accept when they register to those services. The same technology that they abuse enables a lot of useful things. Blame the services, not the tech.
Agreed, I don't see why I need to live with an abusive app and try to restrict is capability to abuse me. Instead, I should vote with my feet and leave.