What is there to dispraise in the defense of the Union?
1) Lincoln's suspension of numerous constitutional rights (habeus corpus, free press, e.g.);
2) The destruction of states' rights as an operative political doctrine, and the substitution of non-negotiable federalism;
3) The first pass at an income tax;
4) The corruption of the procurement process for Union supplies and materiel;
5) The lukewarm and ineffective way in which the war was waged under Scott, McClellan, & Co. in the early stages;
6) A lasting legacy of overbearing paternalism that borders on hubris, that defies the spirit of this nation's founding, and that has been exploited to force unconscionable uniformity throughout a polyglot culture.
Other than that ...
Another poster had it right: BOTH sides can claim their heros and their scoundrels. To suggest that Confederate soldiers were not driven as much by honor as Union troops is absurd and chauvinistic.