The tk2dCamera aligns coordinates not anything specific. In this case your tilemap sprite collection has origin set to centre, so the tile map 0,0,0 is the centre of the first sprite. If you want to fit the bottom left to 0,0,0 you will need to set that up in the sprite collection - select everything, set anchor to bottom left, click Apply and then Commit. Your tile map should now fit in the camera.