When Lincoln suspended habeas corpus in 1861 it was limited to the Maryland area. He was faced with a rebellion, the safety of transportation of troops and supplies through Baltimore was in jeopardy, and Washington, D.C. was in danger of being cut off. He acted as he saw fit and, as Chief Justice William Rehnquist has reminded us, the Constitutionality or unconstitutionality of his actions have never been decided.
Fast forward a year to the south when Jefferson Davis forced a suspension of habeas corpus through the confederate congress. What was Davis afraid of? Why did he need to take this most basic right away from the southern people? His legislation was used to by local military commanders to declare martial law in southern cities miles away from the fighting. What about these abuses? If you believe that Lincoln was wrong then surely you agree that Davis was just as wrong as well, don't you?
That was his tough luck. The Constitution did not allow him to do what he did. Maryland was not rebelling.
As for Davis, I honestly don't know the circumstances surrounding his suspension of the writ. Might he have had to act because of Lincoln's initial unconstitutional aggression? War really wasn't under way (esp. w/Maryland) when Lincoln did what he did. The US is supposed to protect the states, not invade them or take them over. This is quite obvious to you I'm sure. I'm puzzled as to why you can't be objective enough to find fault with Lincoln. He also advocated secession - of West Virginia fm VA - in clear violation of Article IV section 3.