So it's a very serious problem which I think people on this forum are underestimating. Cryptolocker could destroy Bitcoin just like the blacklist can.
Mike's core concern, based on the thread on the Foundation forums, is that Cryptolocker is a serious problem, and because it's such a demonically simple way to extort cash from people, it's going to become a
huge problem. There will be many, many copycats soon, and you get enough non-techies getting ripped off and having their first experience with bitcoin this way, and suddenly govs around the world become very hostile to bitcoin (vs barely caring about it, and figuring out how they feel about it as is the case now). And then (or perhaps before), you can kiss any hope of business acceptance of bitcoin (something we all dream of, I'd imagine, so that we can transact in bitcoin without having to resort to exchanges) goodbye.
The moral panic has long been a powerful weapon in the arsenal of authority. Let's look at a similar "serious problem" from recent history: 9/11. It was so "demonically simple" to hijack airliners and fly them into buildings, that Something Had To Be Done. Similar to Mike Hearn's proposal, the US Government took the opportunity to "temporarily" severely curtail our freedom and massively expand police authority. They also used 9/11 as an excuse to get into some wars that they wanted to fight anyway, even though these wars obviously had nothing to do with 9/11. "Temporarily" has since proven to be "permanently." Bush is long gone, yet the government still hasn't rolled back its expanded powers.
Mike Hearn is participating in the same sort of thing that the Bush Administration did in 2001. He is proposing that Bitcoin businesses voluntarily help the US Government seize worldwide control of Bitcoin for the mere perception that something is being done about CryptoLocker. Meanwhile, there are obvious ulterior motives in play. To achieve a critical mass that would harm all users of Bitcoin, he only needs to get BitPay and Coinbase on board.