There is no conflict between using just force and having some form of normal international relations.
The point is - he wasn't ruthless. He was very indecisive. I don't think he was very effective, either.
We had little strategic interest in entering WWI - the League of Nations was a disaster, and the successor to that, the UN has been even worse. I'm not arguing he had bad intentions, I just think he is way, way overrated as a President (as are many Democratic darlings, Clinton included.)
Likewise, Republican Presidents are commonly (not always, they are on Lincoln's jock, big time) underrated. Herbert Hoover was dealt a really bad hand and is given no credit for what he had to deal with - although I don't think he should be at the top, he should be higher, generally. Likewise, W is typically ranked down in the bottom 25%, with Grant, Buchanan, Harding, and that lot. Reagan is commonly, scandalously, ranked behind LBJ, who is somehow up there with the pack including the younger Founding Fathers.
Just silly the hindsight and revisionism that goes in to pursuing a particular agenda. In the one poll that included POTUS, he's several spots ahead of Reagan, JQ Adams and H.W. Bush.