The most accomplished Confederate General (South) was General Robert E. Lee, commander of the Army of Northern Virginia.
General Ulysses S. Grant led the Union Army during the later years of the war and later ran for office, becoming the President of The United States.
Several reasons.
Saw this crusade as a blessing from God.
Christians would stop fighting themselves.
Christians that would fight would go to heaven or be right with God.
To take back the holy lands, from the Muslims would be a righteous cause.
Voting and serving in the military are voluntary personal responsibilities or rights in the United States. The United States has a voluntary military and therefore it is not required that citizens join or work in the military unless they voluntarily choose to do so. In addition, it is not compulsory that citizens vote and instead it is something that they voluntarily decide to do.
The Geocentric theory or model proposed that the Earth was the center of the universe and the Sun rotated around it. Religion played a big role throughout history in trying to perpetuate this scientifically erroneous idea, which started appearing as a biblical perspective pointing towards specific passages in the holy book. A classic one would be Psalms 93:1, in which Earth is described as a static place "established, firm and secured". The church's support of geocentrism can be traced back to literal intepretations of the bible and a refusal to lose credibility and power as science proved them wrong.
Hope this helps!