I am incline to believe that some people currently are master mining the 51% BCH attack as we speak. If I understand correctly they have to be mining with more than 51% of the current hash rate and they decided to say start a new chain at the very beginning and put in a hashing rate twice or more than real BCH hash rates they will be catching up at half the time. To do it three folds or more cuts the time even more. Who is not to say this can not be done?

A lot of the commenters made good points that other smaller altcoins can be affected. This is disappointing to here because in decentralized world all coins start at zero hashes. So to have such an easy way to ruin POW coins makes this technology obsolete. The growth possibility for any coin that has not been established for many years would never see the growth like btc. I wonder if programmers have developed math difficulty algorithms that can stop a 51% hash attack. That type of coin can be prove it worth in value beyond any other POW coin.