I think that's because they don't understand or don't care about the risks. Annoyingly I was in the process of making my own version of this campaign when it launched but I was aiming to explain why someone should care that the os is no longer supported and why its a problem first, then suggesting what to do about it. Options weren't exclusively Linux but I realise buying a new device isn't always an option either so some people will absolutely keep using 10. It's not about getting to 100%, just enough that you can make a difference or keep devices out of landfill.