Some Data to Analyze : GNU Manifesto (some selected quotes)
consider that the Golden Rule requires that if I like a program I must share it with other people who like it. Software sellers want to divide the users and conquer them, making each user agree not to share with others. I refuse to break solidarity with other users in this way. I cannot in good conscience sign a nondisclosure agreement or a software license agreement.
So that I can continue to use computers without dishonor, I have decided to put together a sufficient body of free software so that I will be able to get along without any software that is not free.
Here RMS explicitly states that using and making software exists in some sort of moral universe where actions have moral implications. A central tenet to RMS's morality is evidently the Golden Rule which he defines as: "I like a program I must share it with other people who like it." By sharing RMS means of course sharing the code and all the rights to the code. If software is made, used or distributed in violation of this moral principle it dishonors the program and the user; cursing the software.
Thus, according to the GNU Manifesto, Free Software exists to make the fulfillment of our moral obligations possible. At the beginning of the Manifesto RMS says the movement needs money. The OP is advocating for providing such money on a monthly basis as a way to fulfill our obligation to ensure software can be used morally.