While I agree with most of the practical consequences of this article, the language is very misleading.
Price is discovered after successful exchange. And it is valid for that exchange and does not mean anything for the next exchange. Thus there is no such thing as price manipulation. You either get or sell something for the price you wanted or not. Faces you make during a poker game are not binding, the cards and your choices are.
As such, there is no price manipulation on the markets.
With paper Bitcoin - all is well if all market participants know what they're buying. If I'm buying a future, I know it's a (possibly cash settled) bet on a future price. It's ok if someone does not want to settle in kind, in many cases that's too expensive. If a gold producer wants to sell an ounce of gold in Papua new guinea in the future and the buyer is in Argentina, they do the in kind spot trades on local markets and settle the difference. This is ok and an innovation of financial markets. Same with options.
You are not entitled to any price and thus this rhetoric of manipulation does not make sense. Yes, Bitcoin is a fixed cap asset. But exchange value is still on whether you are able to find a counterparty or not. Cancelled orders don't matter. Paper Bitcoin does not matter.
Fractional reserves are a problem, swapping to your wallet is definitely a good idea. But the way Kraken does reserve proofs is still ok. You should still withdraw immediately if you are not trading.
Good point about rehypothecation of collateral on lending platforms. Use Firefish which has exactly this property.