up the coin they were mining, there was no other coin to switch to. If you can bribe someone to vote one way or the other, or you just want to mess with BCH for ideological reasons,
you can do so at almost no cost. You only need 51% of the total hashrate, which is in turn maybe 10% of the total sha256 mining power, so you need 5% of that. What's worse,
if you start mining BCH after it becomes marginally more unprofitable, because you're also compensated by a bribe or by an ideological payoff, rational honest BCH
miners will switch over to BTC, leaving only the attackers mining BCH.
