the essence of their attack on bitcoin is to scare small node runners away from performing full network service by making blocks unpalatable. they are muddying the waters to increase uncertainty. the attack won't work to impact bitcoin, per se, because big miners can't be risking liability any more than they already are. but driving node runners off the p2p network will reduce their influence on governance of bitcoin when they conveniently roll out a new USAF to "solve" the problem, they will get what they want.