That doesn't answer the why, however, which is being asked.
Currently, I am mobile so I cannot be detailed. Short answer is Microsoft is to blame here. Driver signing changes were made necessary by Microsoft. Microsoft also ended Vista support. Vista x64 requires driver signing. Vista x86 does not. It is possible to turn off driver signing in the OS but it's a bad idea for security reasons on an already obsolete and end-of-life OS.
In short, RedFox isn't trying to hurt people running Vista x64. It's Microsoft that is causing this.
Microsoft is guilty of a lot of things, but it is not their fault, that we can't sign the driver with a SHA1 cert.
You can't even really blame them for not updating the kernel to support SHA2, as Vista mainstream support ended April 10, 2012.
Rest assured, we would sign it with SHA1, if we could. You're right, we're not trying to hurt people, but we have no choice.
However, AFAIK you can permanently disable driver signing enforcement in Vista (later OS versions won't allow this). I can't predict the risk this involves, but I doubt this makes much of a difference for an OS which no longer receives security updates (extended support ended April 11, 2017). There are probably much easier methods to take over a Vista machine than distributing an unsigned driver and hoping, that the user has disabled signature enforcement.
EDIT:
Here is a How-To (use Method 2 for permanent disable):
http://www.overclock.net/t/187919/how-to-disable-driver-signature-enforcement-in-vista
EDIT2:
Afterwards, AnyDVD can be installed with the /NoSHA2check command line parameter.
EDIT3:
I haven't tested this myself, so feedback is welcome.
