No, they aren't.
Special Forces QC is a separate qualification from
Ranger school. Some Rangers (primarily the
75th Ranger Rgmt) work for
JSOC as
Special Operations Forces but
SF is separate and distinct from SOF. Even the Ranger school grads acknowledge there is a wide gulf between being "Ranger-qualified" versus serving in a Ranger unit.
The vast majority of soldiers who attend Ranger school do it just for the career-enhancement or bragging rights. They'll never serve in even an Infantry unit, much less a Ranger unit. Most just go back to the whatever job they had before; aviator, JAG lawyer, tracked vehicle mechanics, clerk-typist, ... whatever. But simply the fact that you were selected to attend SFQC means there's an SF job waiting for you if you manage to graduate.
The 75th only got absorbed by JSOC because Sheikh Obama (piss be upon him) was so afraid of the fallout if the demoncrat peace-niks discovered how many people he was ordering killed that he used clandestine means for doing his dirty work. But he was very ambitious in his killing and set the operational tempo of the SpecWar community so high that they were wearing out snake-eaters faster than they could be replaced. It takes 4-5 years from enlistment to grow even a minimally-qualified "operator," and two or three years more if you want one with some experience under his belt, so you need close to a decade to prepare for the accelerated attrition that Obama (PBUH) pulled. But if the length of the supply chain posed a problem, the 75th Rangers offered a solution. They had a similar discipline, work ethic and physical hardness as SF, many of the same skill sets, and many of them already were battle-hardened.
So JSOC 'requisitioned' them from the Army. Which is how the 75th comes to work for DoD's (interservice) JSOC rather than the Army's SOCOM.