Indeed, which is why NITAT was formed.
In reality, some of the things which happened were truly brutal and uncalled for.
But with tens of thousands of troops, hundreds of thousands over thirty years, percentage wise, the professional outweighed the unprofessional.
That's it in a nutshell.
It's worth remembering that the army had withdrawn from Aden just 2 years before the Troubles began.
There were things that were common practice in Aden that would cause an international outcry and war crimes trials today. Some acts of brutality were (arguably) necessary evils, others were truly shameful.
It was a very different kind of army that hit the streets of Belfast in the early 70s. Much rougher and tougher, a lot harder and a lot less compromising than today's army. It was a different generation with its own values and worldview. WW2 had ended just a quarter of a century earlier...
The only real surprise is that there weren't more tragedies like Bloody Sunday.