It's got nothing to do with Backdoor code, the reason you can't run the disk version on Windows is very simple. It needs a driver to validate the SafeDisc 2 DRM on the disk, before the application can be run. Since Windows 10 removed this driver altogether, it simply fails to start. MS then removed the driver in an update to Vista, 7 and 8 versions of Windows, claiming it had a security vulnerability. It's not such a problem on these older O/S's, since you can use a workaround, but if you are on Windows 10, unless you want to manually digitally sign the driver, you have to buy it again.
The very same game code, but in digital editions, works just fine, because the Safedisc code was removed, since Safedisc is only applicable to optical media, this wasn't so much a choice. Some vendors, Steam and Origin replaced Safedisc with their own DRM systems. The problem with Origin is that they don't sell you a patched version of the game. But the changes to the .exe (adding their DRM) cause the official patches and BAT installer not to recognise the SC4 install as genuine. The solution is to update these installers to correctly recognise the modified versions as legitimate. But that's not going to happen, at least when Origin bothered to include the patches with the digital release, that only caused problems installing SC4 BAT. But now they've reverted to the unpatched version, users are getting screwed.
To be clear, there is nothing relating to the SC4 code that is in the slightest bit incompatible with Windows 10.