I think you are probably correct. People seem to be conflating your William with a child called Absolum Hooper from the 1880 census,
"United States Census, 1880," database with images, FamilySearch (
https://www.familysearch.org/ark:/61903/1:1:MDQR-3BZ : 5 January 2022), Absalom Hooper in household of John R. Hooper, District 11, Grainger, Tennessee, United States; citing enumeration district , sheet , NARA microfilm publication T9 (Washington, D.C.: National Archives and Records Administration, n.d.), FHL microfilm .
who was the son of John R. and Selina Hooper. That child was actually Robert Absolum Hooper, born in March, 1873, per his Tennessee death record
"Tennessee Deaths, 1914-1966," database with images, FamilySearch (
https://familysearch.org/ark:/61903/1:1:NS82-M9H : 1 March 2021), Robert Absolum Hooper, 13 Dec 1921; Death, Nashville, Davidson, Tennessee, United States, Tennessee State Library and Archives, Nashville.
That doesn't help you find William's real parents, I know, but I think it definitively shows that John and Selina are incorrect.