True, but he also started the Jedi Civil War. The whole point was to help stop what he created, which was the war and Malak. The Starforge was added after you figure out how Malak was creating his army, it wasn't the driving force at the beginning.
In either case, it really doesn't matter. People lived Revan's story. I for one picked him to be a Sith. But I don't feel cheated by the change. We all knew that they would have to pick an ending. Such is life. That for me doesn't break any of the connection I had with the character.
But to each their own. The point here, as it's really easy to figure out why people like Revan.
You are confused.
When Revan and Malak reintroduced themselves to the known Galaxy - not as saviours but rather conquerors - they were ALREADY
using the Star Forge to fuel their war effort.
Revan had abandoned known space with only a handful of ships, in pursuit of whatever Mandalorians has fled the battle raging over the skies of Malachor V. When he returned, he was in command of a vast armada
, not only a couple of ships.