The 75th Ranger Regiment is not a SOF group.
They are are just highly elite light infantry force assigned to SOCOM with the objective to conduct special operations in support of SOCOM missions.
The training is different because, from other Spec Ops, due to the different mission objective. Ranger School is a ball busting, humbling experience, course designed to strip you of your manhood. It is designed to mimic the stresses, a Ranger will see in combat. Through this, Ranger students learn the necessity of planning, execution, teamwork. Leaving no stone unturned, no leader is considered a leader unless he faces the same experiences of those enlisted. Leaders earn their place, it is never given. Ranger School is designed to stress individuals to their physical limits in its three weeks and to expose those who are unable to be team players under stressful situations.
Once a soldier has been selected, then the emphasis is to build upon that soldiers' physical fitness and qualifications that were screened in his application (GT score = general aptitude and intelligence, DLAB = language aptitude, etc.). The end state of SFQC and the follow on training is an operator capable of both detailed planning and the capability to interact on missions independent of higher command but within the intent and purpose of their mission.
So, I'd say that while the Rangers would fall in comfortably within the direct action spectrum of the Spec Ops mission, Spec Op teams cover much more ground in their FID, SR, UW, and CT missions. Follow-up training is regularly given to enhance the Ranger's unconventional skills required from them.
In other words, each American Spec Ops team is elite in their own rights. Each Spec Ops Tier, has different missions, although they share some of the spectrum of special operations.