As it was not an attack on BTC (any BCH pump seems very suspicious for me) that can be concidered as a some kind of correction after a pretty big growth. I'm sure that it is pretty good and it will help from the psychological side: a lot of people are waiting for the end of this year to see the final BTC rate and they can easily dump it especially if it is uncorrected. If bitcoin will continue its slow growth it will just make the situation more calm.
Both things converged: A correction was due naturally, as we were under a massive bullrun, and the BCash manipulation with the mempool spam and the Coinbase bribing to list it right during the difficulty adjustment to create as much confusion as possible, also was a way to create a dip while dump a very pumped BCash. The whales just want to accumulate as much BTC as possible, since they are scared that LN is working, and will solve the scaling issue once and for all.