It is not a completely invalid what he states, although the tone could have been better But there are risks in having them on exchange sites given the history of some larger exchange sites that closed suddenly and froze/stole people's balances. Once the market matures a bit more and becomes better regulated, this risk will lower.

Back to the point, there is an excellent post here above that actually describes it thoroughly and well.

It is all theoretic that extra money is created during forks. When a fork occurs and people get additional coins they hold no value of significance until there are buyers in the picture. So to get the market going that still also will require some liquidity injection. This will have to come from other cryptos and even bitcoin.

Price fluctuations at this level is definitely to be expected. Bitcoin's price is in a completely new territory never tested before, so it is almost impossible to know what to expect at this point. It depends how much more liquidity is being injected into Bitcoin in the near future, for whether or not the steam can be sustained. Long term however, I think we can all agree that Bitcoin has not seen its height yet. It is gathered increasing momentum in the real-world across media outlets. As coins start to get regulated this will help brand awareness and adoption in general.