Free State Army was just a normal (legal) Army.
You're getting a bit caught up with the good bad thing.
It's important not to colour events of the past with more recent events.
Exactly what I was thinking.
The situation was (and is) complex. What happened in Ireland 100 years ago was a part of 700 years of sometimes violent history in Ireland, Britain and Europe. The current political impasse between the three is a legacy of the partition of Ireland almost a century ago.
The war of independence and the civil war which followed split some families and fractured friendships.
Some participants believed they were fighting for a noble cause, whichever side they were on. Each of the many sides could argue that they were defending their country, or their part of the country, or their community, or their comrades. In the course of that, some took actions or made decisions which they would not have done in normal times. Good people did bad things. Some actions were pro-active, others were reactive. People got caught up in events over which they had no control, and their freedom of action and decision-taking was curtailed. Each action from the Volunteers provoked repression by Crown forces, which stoked resentment, leading to further action, followed by increased repression, and so it escalated.
One side's heroes were another side's villains. Heroes became villains and villains turned into heroes in some cases.
The only certainty is that everyone is a loser in a civil war.
The outbreak of World War 1 caused a split in the Irish Volunteers. Many joined the British Army.