A couple readers ride to his defense:

Jonah,
I’m sure you’ve heard from a number of Forrest fans, but to characterize him simply as ruthless, as one reader did, doesn’t come close to describing his exploits. He was, above all, an innately brilliant strategist, personally audacious in battle, who was feared by his enemies (Sherman among them) for the reputation he earned winning battles in which he was a decided underdog. After the war, General R.E. Lee said Forrest was the finest soldier he had ever commanded, even though he had never met him.
As to identifying him as a racist, as did another reader, that’s a topic far too complex to go into here.

And:

Dear Mr. Goldberg –
Re your previous correspondent’s characterization of General Forrest as a brutal racist, there are plenty of indications that the general’s character was a little more complicated than that. Cf. http://www.dixieoutfitters.com/heritage/cw39.shtml
While it’s politically incorrect to ever defend Confederates, sometimes it’s truthful to do so.