Not only are disposable diapers not taxable, not only do diaper services generate individual income, not only are they taxed via that income and other methods, but apparently diaper services are less expensive in the first place:

For Representative Handy, who apparently has trouble with numbers, that means on average that it costs a mother $2,075 to buy disposable diapers at the store and $910 per year to use a cloth diaper service.
As a former owner/operator of a Rhode Island-based cloth-diaper service, I can confirm firsthand for Mr. Handy that the majority of my customers were not Mr. Handy’s luxury moms; they were lower-income households looking for an alternative to the high cost of disposable diapers. By introducing a tax on cloth-diaper services, Mr. Handy and his bill are actually making the less expensive way of diapering kids in this state more expensive for those lower-income households that now use this service as a way of making ends meet.

Expect a rhetoric shift: We must expand the sales tax to disposable diapers! Rich parents like Representative Arthur Handy (D, Cranston) are costing our economy money by contributing $2,075 per year to out-of-state megacorporations, while depriving local loincloth launderers of business.