My understanding (and very limited) is that the Shriners broke off from the Masons who they considered too uptight. They wanted a group with more fun.
To my thinking that disassociates them as they wanted their own group away from the traditions of the first. But I may have that understanding distorted. I see them as a new group, not a continuation of the old.
All Shriners are Masons but not all Masons are Shriners.
There are three degrees to Freemasonry up to Master Mason. After that, a brother can choose to join appellate bodies in the York Rite or Scottish Rite. This is like finishing your Doctorate then deciding to study in another, but similar field. There isn’t bad blood at all. All Shriners are active and proud Master Masons.
They’re a different organization whose requirement for membershipis that a man be a Master Mason is my understanding.
The basic Masonic Lodge is the blue lodge whose highest rank is Master Mason. Then you’ve got your York Rite and your Scottish Rite. Fromerly, a Shriner had to have completed the degrees in one of those rites.
Then there are a bunch of other organizations that require Masonic, that is Blue Lodge, membership