Not in France. You are reasoning by the US law while the only applicable law is the french law for my case. I can raise a legal recourse against the one who stole me a virtual good.
By the US law, this is aswell false regarding the two Bitcoin platforms owners that are going to be trialed in US. If I remember correctly, they're charging them both for money laundering using a virtual currency, which should not be, according to what you said, possible.
Plus everyone that are doing a class action against BTC Market when it appeared to be clear they were running a ponzi scheme.
And utimately, PLW's ToS have nothing to do. The analogy you're doing is the same as if I was sharing a car wit someone who ran off. I'm raising an action against the one who ran off with the car and there's only the law that applies, not a contract I signed between me and the car constructor (which of course will say he is not liable if I share my car with anyone else).