Mosheemes explained it beautifully. There is no question anymore. The only question which remains is why this or that person was Zoche? This type of question, however, is not the kind that will get, nor deserves, an answer.
Harugei Beitar, who’s Frumkeit I’m not sure about (they killed Reb Elazar Hamoda’i), died in a battle that they fought for nationalistic reasons. And yet, Chazal tell us that nobody can approaach their spot.
The Gemara says that one who gives Tzaddaka so that his son should live, is a Tzaddik Gamur. The Maharal explains, besides his other Pshat, that asking for a Yid to live is actually Ratzon Hashem. That in itself is a Mitzva. Like I mentioned in the other thread, it is a Kiddush Hashem when Jews have a Yeshua and when things go well. Therefore, those who die for the cause of Jewish people have died for Hashem, Who’s name is tied to us.