Since the (supposed) desired purpose of this mechanism is merely to offset taxes paid on "necessities",
Merely to offset, is not true. The FCA helps prevent a class of citizen from not paying any tax at all, by assuring everyone pays the same tax rate on all the retail goods and services they purchase.
Exemption of payment of a tax creates tax privileged groups as readily under a retail sales tax as under a graduated income tax.
FCA assures the basics as determined by the citizen are covered. But all products remain taxed for all citizens regardless of personal circumstance. All citizens remain intimately cognizant of cost of government in their daily lives, from the poorest to the richest, from those who receive much from government to those who receive none. They all share in the payment of tax due at the retail register.
It is only in knowledge that we can exercise vigilence and hold government accountable. Everyone must participate in the tax system even the poorest among us.
Argue to get rid of the FCA, and I could agree as a matter of principle. Don't argue that we must relieve groups of folks from participation which the exemption of a broadrange of "necessity" goods and services would create.