Who's we? ... good news btw.
I'm not their spokesperson but I guess it's the university researchers (prof & his students) working on their papers and this is the implementation. I wonder if they heard of testnet and bothered to add a flag to run on testnet before potentially destroying real coins
My guess is that this library isn't in any way made for Bitcoin, but is simply a group of functions that handle the cryptographic aspects of zerocoin. Ie. it abstracts away the underlying cryptography into functions that can be used by programs that wish to use this functionality. It would be someone else's job to integrate this into Bitcoin, if so desired (which, I gather, it is not). But that's just my guess. If this weren't the case, I think they would announce a fork of Bitcoin-Qt and not something called "libzerocoin". But we shall see.