I was not in the least bit surprised that what followed this disclaimer was by and large the same tired anti-Bitcoin arguments we've all been reading since 2010. Not to mention the title is a gross exaggeration and undoubtedly fishing for angry clicks.
The worst part is there's a nugget of truth hidden amongst this FUD: the danger of ICOs and other varieties of altcoin scams. There's really no value being created when yet another coin is created that's just an existing coin with a new PoW algorithm stapled on, yet the creator stands to make tens of thousands off of his or her 2% premine, because of people speculating that this might be the Next Big Coin.
For this reason, I think the cryptocurrency market is definitely in a speculative bubble. But so what? So is Silicon Valley. Is a Wi-Fi enabled plant waterer really worth $30 million in VC funding? Probably not, but that doesn't mean the Dropboxes and the AirBnBs of the market aren't adding value. The abundance of worthless altcoins doesn't mean the cryptocurrency market as a whole is worthless, but it does mean you should be careful what you invest in.