He would be the clear choice of the voters.
but he wouldn't be the clear choice. if a candidate gets less than 50%, that means more people don't want him than do. hence the need to do multiple rounds of voting until a candidate does get an actual majority.
Maybe "clear choice" wasn't the right way to put it. He would be -- let's agree -- the most popular choice. There's no way he has a distinctive lead on second place, loses it in the convention because he fell just short of 50%, and that huge number of people who went out and voted for him aren't going to feel disenfranchised, rules be damned.
From a pure "fairness" standpoint, I agree with him. Taking it out of the hands of the actual voters so people can make some backroom deal seems, on its face, very much against the democratic process. Lots of general elections end with people not getting to 50%; I think if that situation was handled the way a primary handles it, people would be so outraged they'd demand the system change going forward.
