Most importantly though, one should refrain from making demands on people who are offering you things for free.
If you like the code and are willing to use it under the terms provided, use it. Otherwise you're no worse off than you were before. Write your own version and get on with life.
or taking the JSON grammar and implementing it from scratch. It's not exactly complex, the most complex part is strings and even those are rather simple.
It seems like this Debian developer is mad because an author didn't write a license the way he want it written?
That's not an option for Free Software distributions like Debian, so everybody loses except evildoers.
He may not go for it, but they are certainly capable of asking.