The DAA is enforcing the planned emission of coins via the difficulty, making sure that nobody could instamine and create temporarily a huge "inflation".
The DAA can not protect against a 51% attack. We have a 51% attack, not (only) a timestamp attack. Someone had to find those blocks before he could submit them with a faux timestamp, hence 51% attack.

This attack maybe also explains the extremely irrational selling behavior in the days prior to the fork. The person or entity which dumped all those coins (I guess a ASIC miner) was obviously in a hurry to cash out. It's entirely possible the same person/entity is now behind the attack, having a huge war chest to rent the nicehash botnet and rape the chain.