He is concerned with a deep problem. Those of us who are "minarchists," meaning that we favor government that is limited to adjudicating conflict, have no reliable mechanism for restraining government.
His point is that government can use its rule-making power to remake any rules that were used to create it. Certainly, we have seen this in the United States, where I would say that the original Constitution lies in shreds.
He concludes that only irrational standards or taboos can constrain the power of government. I tend to agree. If there is no taboo against government interference with activity X, then as long as it is in the interests of the governing coalition to interfere with activity X, that will happen.
This really seems like a special case of a larger problem that anyone who favors any restraint of government has to deal with. I've heard basically this argument advanced in favor of anarcho-capitalism, but of course one of the biggest problems with any anarchism is that unless you can secure unanimity (in which case you had better not imagine a polity where n>1), some form of coercion seems to be required in order to prevent people from forming governments. Even with strong taboos, has there ever been a society that actually succeeded in controlling the size and shape of its government in the way that libertarians imagine?