It does not matter if they were raised protestants, since those religions have history like islam does.
Ennis was raised Methodist, which is punishment in some ways like islam is... and same with Jack being Pentecostal (which is death too) which is also like islamic in many ways; or like those japs who flew planes and killed themselves on USA, Canadian, English... boats in the name of what again ?
There are some islamic ways in christians and jews and in some other religions then and to-day, but not much is talked about that ! Catholics and others like ones stated have changed somewhat refraining from islamic-ideas and ways (like accepting gay marriages and gays a bit), but much remians yet as anti-life !! Some christians used a whip to whip themselves daily as a routine, and still to-day even if the Catholic church refrains from that now, but which was a demand and in demand by their religious orders, did you know ?
Plus, Ennis' dad did show that dead tortured body of a gay man... isn't that like some islamic groups do ?