Why should you design your software around what a different piece of software could claim of your program?

Because you want someone who trusts that different piece of software to use yours.

Zig's decision here means the problem is _yours_ to convince this third party to trust you.

The idea/hope is perhaps that the Zig programs will be of better quality than other programs, which will make it hard for the other side (the antivirus) to justify its position in a reasonable way. And in the end the other side will be forced to change its processes.