The theme of this propositional manifesto is that money is something that makes people happier, and money doesn't cost that much to make, so why don't they make more of it?
The short answer to above question is that increasing the total amount of money does not increase the total amount of wealth (or of happiness), and actually leads to hyper-inflation and destroyed economies.
Most people wish they had more money, and most people experience an immediate feeling of happiness whenever they discover for some reason that they have acquired some money that they did not expect to receive. Conversely, most people are unhappy when they unexpectedly lose some money.
What actually makes people happier is not money, but the things that money can buy.
The basic fallacy of this manifesto is the failure to distinguish between the value of money to an individual and the value of money to society as a whole (where in this context "society" refers to the country or countries which use a particular currency).
The value of a particular quantity of money in a particular currency is a function of what proportion that quantity is of the total value of the currency, and how large is the economy which uses that currency. Creating new money in a currency can not increase the total value of the money in the currency. If anything, it will reduce the overall value of the currency, in as much as the creation of new money devalues existing money, which reduces the desirability of using or holding that currency, which reduces the total size of the economy using the currency.
Creating new money does not create new things to buy with that money, although if may reallocate wealth from one group of people to another.
In most countries, most items of currency cost less to manufacture than the actual value of the currency item. For example, a US $20 note costs much less then 20 dollars to manufacture.
It is true that most currencies are cheaper to manufacturer than their face value, although it should be noted that most money is designed to be very expensive for anyone other than the official issuer of the currency to manufacture, specifically to prevent individuals from creating their own money. Creating your own money is called "counterfeiting", and if caught, you get sent to jail.
Most governments, especially democratically elected governments, exist to serve the needs of the people that they govern, and one of their most important jobs is to maximise the happiness of their subjects.
Yes, governments should seek to make their subjects happier. However, creating an unlimited supply of money does not increase happiness. In the short term it may increase the happiness of those chosen to receive the new money, at the expense of those whose existing money holdings are devalued. But in the long-term it leads to inflation, or even hyper-inflation, with an associated disruption in economic activity, where people put more effort into spending their money as fast as possible before it loses value, rather then putting effort into doing things that create wealth.
If you have read down this far, just remember that this propositional manifesto is an example.
The critique (which perhaps should be taken more seriously than the manifesto itself) can be found here.
On a somewhat serious note, it may be that writing an ironic propositional manifesto is a good way to argue against a point of view that you disagree with, especially if the person arguing for that point of view hasn't yet written their own propositional manifesto for you to critique it.
This paragraph is an example of part of the critique in the appendix. (The first three paragraphs in this appendix were part of the original manifesto. In a real manifesto, the original manifesto would not contain any references to the critique.)