Hiya gang!
I'm bashing my head against a stubborn family of Dargans at the moment. They're a mysterious bunch

Seems one Charles Dargan (variations Dargen Dargin Dargon etc) had three children that I can find: Chester b 1822, Francis b 1827, and Eleanor b 1828. All in Antrim county. The family migrated to Belfast where the children married a McAffee and two Campbells (siblings).
So these are Scottish names and the families are known to be Protestant. But Dargan is a pretty Irish name and there are only 2 Protestant Dargans in the 1901 and 1911 censuses. The rest are all Roman Catholic. Somewhere back in time, my Dargan family seems to have converted to protestantism.
I'm asking for some practical insight into why the family might have done this. Apart from theological reasons, like someone was reading his Bible and came to the conclusion there was no need for priests etc...this kind of thing would be purely personal, subjective and impossible to prove. I'm looking for some kind of pragmatic reason.
I know it's a touchy subject in Ireland, but I'm not from there and have no idea how to approach the matter. Thanks if anyone can help

Cheers,
China