Hamas said it was not responsible for the rockets. I've never noticed any reluctance on the part of Hamas to claim responsibility for attacks they have instigated. One thing you can say about them, right or wrong in their behavior overall, they're pretty up front about what they are doing.

Hamas should no more be held responsible for actions taken by other groups in areas over which it has control than the Isreali government should. The Israeli government does not do anything at all to prevent or stop settler attacks on Palestinians. On the contrary, it assists those settlers in getting away with those attacks. Double standards for behavior don't work in the long run. Not if peace and security is the goal.