UnchartedSpirit said:
... So I'm asking: should we really be trying to wage war over other Christian demonations,...
No; the Bible condemns this activity.
Titus 3:8b-9a “I desire that thou affirm confidently, to the end that they who have believed God may be careful to maintain good |deeds|. These things are good and profitable unto men: but shun foolish questionings, and genealogies, and strifes, and fightings about law; for they are unprofitable” (ASV|NLT 1996, RSV 1952|ASV).
Our priorities as Christians should be good deeds. We must refrain from any "strifes" over "questionings" that have no relevance to good deeds.
1 Timothy 6:3-4a “If anyone advocates a different doctrine and does not agree with sound words, those of our Lord Jesus Christ, and with the doctrine conforming to |a godly life|, he is conceited and understands nothing; but he has a morbid interest in |disputes”
Christians too often use this passage to rationalize their warring quarrels -- as I did years ago -- but it actually teaches against them. In every context where KJV "doctrine" is mentioned in 1 Timothy, it refers to matters of regular life. Here, it is specifically "the doctrine conforming to a godly life" that we need to focus on. Anyone fixated on teachings that have nothing to do with "a godly life" is one who "understands nothing" and "has a morbid interest in disputes."
There is a difference between peacefully discussing matters of disagreement, and feuding. Unfortunately, there is a lot more of the latter than the former.
...even Catholocism, if their souls are really on the line over this sort of thing? Does it really make a difference then if they're dammned if they're following the 'wrong' demonation or choose to remain lost just because what they followed was proven to be so erroneous?
When Christians depart from their church congregations and go back to their regular lives, we all pretty much agree on everything. Christians are Christians at all times, and I simply do not believe any Christian ever ceases to be a Christian a few hours per week.
I do not give any building or group of people the power to get salvation revoked. Romans 8:38b-9 assures Christians “neither death nor life, nor angels nor rulers, nor things present nor things to come, nor powers, nor height nor depth, nor anything else in all creation will be able to separate us from the love of God in Christ Jesus our Lord” (ESV). “Anything else in all creation” includes buildings made of created materials, and includes other people; meetinghouses, people using them, and church congregations do not have the power to unmake a Christian.
Being a Christian is about being a follower of Christ. I see no biblical merit to any belief that Christianity is about agreeing with the `right' group/s of people. If a person is a follower of Christ, s/he is a Christian.