The problem with things like iOS is the user can't make that choice. Also what you call 'bad' is up to the user. At the end of the day a user should be able to adjust things even at root level or request other software to do that on their behalf. Heck for iDevices owners should be able to load their own signing keys at a minimum for the Boot-ROM.

As for Adobe most people would not expect their software to touch the host file, so it's fine to call them out here. Someone using a utility or tool that you would expect to edit the host file that's fine, and people should be able to use or make such a tool. (The os should not prevent the user/owner if that's what they want).