Nope - they went out because they were offered jobs, an easy war and meals every day, which many of them did not have at home.

There was plenty of well paid civilian war work available.
Most joined during and after the retreat when there was no hope of an easy or quick victory, and defeat much more likely.

Expalin the sudden U-turn - from support for Britain to a War of Independence that drove Britain out of Ireland in a matter of months.

The British misjudged the situation and Ireland sympathised with their martyrs.
Britain was not driven out of Ireland in months. Home rule had to wait for the end of the war when it would have happened anyway.
All the bloodshed of the Rising was irrelevant.