Jim,
- an illegally armed political organisation who re-introduced the gun into Irish politics and threatened to invade Dublin.

That would be the Irish Republican Brotherhood, and they did invade Dublin!

Do you deny that the majority in NI did not want to leave the UK, and were prepared to fight to remain part of it?

No.
It is a fact.
The officers you refer to refused to force them out by killing their former comrades.
They preferred to resign as was their legal right.
There was no refusal to obey orders nor any threat to do so.
Resigning is not a rebellion.