I am quite sure you are sincerely concerned about Lincoln's reputation.
Do you think the Lincoln assassination was a "positive good"?
Killing is never a "positive good" and at best can constitute an act of neutral necessity to avoid a clear bad. What LG was noting is the fact that an unintended consequence of Lincoln's assassination was to put an end to colonization schemes. Had he not been assassinated it is almost certain that colonization of some form would have taken place in his second term and quite possible that significant portions of the black population in this country would be living in Panama today or some other foreign location. Making that observations connotes absolultely no necessary value judgment for or against the assassination itself, nor could it possibly do so given that Booth was almost certainly unaware as to how his act would impact colonization policy either way. Not that any of that matters to filthy liars like yourself though, seeing as your purpose here is only to obstruct and slander others who disagree with you. Sidney Blumenthal indeed.
No, it elevated Lincoln into the American pantheon and terminated all rational discussion of his policies and constitutional pretensions. Had he lived, there would have been some sort of reaction against what he did to the country. His death and monumentalization arrested that.