A is the answer ms.gurl ya welcome
I'm going to answer this as someone who doesn't like k-pop, and doesn't really care about BTS. (Thus giving you an unbiased view)
No. I do not not thing they should serve in the millitary. Not because they are famous or anything. I think that if they do not want to serve in the millitary, they should not have to. I do not think anyone anywhere should be forced or required by law to be in the millitary.
They suffered a loss of steady trade in fur, meat, and grain with European traders.
They suffered negative consequences because they lost both their land and their allies.
They were successful because their goal was to get rid of slavery and have the union win the civil war. They were able to get the 13th amendment passed (with the bribery of some Democrats) and win the civil war in four years.