If a president vetoes a bill, Congress can vote to override the veto. If a president just sits on a bill and doesn’t sign it, there’s nothing Congress can do. This is called a “pocket veto.”
I was unaware of that whole “10 days or it becomes a law anyway” bit, but that’s not relevant here because Congress did adjourn, for Christmas. Seems like there’s some question as to what kinds of adjournments count for the “10-day” thing. Just end-of-term adjournments, or like the Christmas break they just took.
At any rate, Congress doesn’t seem to think there’s anything they can do about this. So I guess we’re all just fucked then. Neat!
Update: Hey, look, the abusive POS signed it after getting his jollies off on scaring the shit out of everyone for a week. Dick.