My take is that the critics possess FOMO and would like to tumble the prices with their tactics before they put some of their flesh into cryptocurrencies. They indeed have been paying close attention to Bitcoin, lately (past year).
"Bitcoin had been closing in on $10,000, but it fell nearly 6% Sunday and was down another 2% Monday to just over $9,300."
http://money.cnn.com/2018/05/07/investing/warren-buffett-bitcoin/index.html
