I never said anything about IOS. However, by switching to GNU/Linux, hacking will be made harder, simply because of the fragmented nature of GNU/Linux: what works on one distro isn't guaranteed to work on another. I realize this isn't a perfect defense, but it's better than being defenseless.
Also, Windows 10 is malware. There's no escaping that fact. By switching to another OS, you are ridding yourself of Microsoft's malware.
I suppose you've got me there. As long as the developers know what they are doing, the user doesn't need to know much.
Since Unix-like systems allow any folder to be used as a mount point, it makes sense to only mount partitions as read-write when necessary.
You're right, all operating systems are flawed. However, it's no accident that the majority of malware is developed for Windows. Before you say what I think you'll say, yes, the large market share of Windows is an important factor. But, the FOSS nature of GNU/Linux allows the system to be patched much more quickly than Windows or MacOS. The problem with proprietary software is that users are forced to depend on the people that made said software for things like security. So, if that developers refuse to issue a patch, the users are left defenseless.
Anyway, my point in the paragraph was this: the US DOD will never be transparent, regardless of what operating systems they use. It's not that they're refusing to be transparent because Windows make transparency too hard. Rather, they are refusing to be transparent because they like their secrecy. Whether they use Windows, MacOS, GNU/Linux, MS-DOS, OS/2, ReactOS, *BSD, Illumos, Android, IOS, or anything else, it won't affect their decision to hide as many things from the public as they do.