In answer to your rhetorical question, "laundry list" refers back to an earlier time, before women's lib (and when men rarely performed domestic chores, even when unmarried), and before laundry machines were available in most houses and apartment buildings - In other words, when people (usually men with no domestic help) sent their laundry out to be cleaned. The list (x number of shirts, for instance, possibly along with a
brief description of each) is an agreed-upon assurance that what went
out is what came back, and lives on today in the numbered and itemized
slips you receive when entrusting your garments to a dry cleaner.
(The administration of my Canadian graduate college ignored the pleas of the Junior Fellows to install a laundry facility until the early 70's. They only relented after one of the Junior Fellows staged a sock-washing in the quad's reflecting pool, timed to coincide with a scheduled appearance of the Visitor. Up until then, the College's firm view simply had been that "young gentlemen send their laundry out.")
Incidentally, the association of the Chinese with domestic tasks like laundry and cooking originated in the American West and stemmed less from their inherent abilities than from their willingness to perform such "woman's work" in places with virtually no women. (It also beat getting abused and/or killed working on the railroads.)
Actually, the expression "laundry list" is misused in most contexts, since it implies an mutual agreement or contract, and should be replaced with a term used in stamp, book and record collecting, "want list." Or one from the game of 'chicken', a "who flinches first" list.
However, a laundry list approach to government might not be such a bad idea. Perhaps we could agree upon a list of rights and freedoms we are entrusting to our leaders and representatives at the beginning of each administration or session of Congress, and at the end receive an enumeration of what we're getting back, so that by comparing the two we can see just how much was lost in the wash.