The dump made the coin look like a scam, which was due to said Korean exchange going temporarily offline and triggering panic sells as well as their underestimation of the amount of money some other big players were willing to inject during the tip. There was an interview with a hedge fund billionaire that invested a modest 8 digits during that dip, preventing the price from going lower.
Had they otherwise been successful in reaching price parity with Bitcoin, it could have triggered mass FOMO with people jumping onto BCH for the "flippening", resulting in Bitcoin bleeding huge amounts of hashing power. Fortunately, BCH's new difficulty adjustment algorithm, which went live a few days after this pump and dump will no longer allow for massive hashing power swings, thereby minimizing the likelihood of them trying this again.