Good question. I would imagine ego had a bit to do with it. However, the fact that various schools were vying for government support probably had something to do with it as well. Keep in mind, this was after WWII and the Korean War, resources were at a premium, and, unlike Japan, nations weren't putting strategies to help rebuild Korea. It truly was like the Old West, with people and organizations settling disputes and grievances the old fashioned way-with their fists (and feet). Add Tae Kwon Do to the mix and it makes for a very interesting situation.
That has the ring of truth... but I can't help feeling as though there was more to it than that. What I mean is, it seems as though right from the get-go, the MA situation in Korea was institutionally competitive and focused on a tapline from the Korean government. But why would the Korean government have that much of a stake in the fledgling Korean MA scene?? My take on the situation, based on the historical research I've cited elsewhere, is that the Japanese training the Kwan founders received in Japan and brought back to Korea shortly before WWII represented the first major infusion in generations, if not centuries, of new material into an essentially moribund Korean MA scene (and for anyone reading who wants to bring up taekkyon, check out both Dakin Burdick's 2000 online article at http://www.budosportcapelle.ml/gesch.html, which synthesizes his 1997 Journal of Asian Martial Arts article with new material, as well as Robert McLain's interview with Gm. Kim in our own MT Magazine archives; you'll see that taekkyon was totally moribund at that point and that no one, including Gen. Choi, was actually doing it or had any instructional connection to it). Why would the Korean government have taken that much interest in something which, at that point certainly, must have seemed an exotic specialized interest far removed from what the professional soldiers in the Korean military were used to and what the civil servants would have been familiar with?
My own take on it has to do with the role that Gen. Choi played, a high-ranking officer with a lot of clout in an essentially military government, who was also a devotee of a particular strand in the evolving fabric of KMA. The reason I think this extra factor is necessary to the explanation is that it's not clear to me why else the government support you mention should have been an issue in the first place... I've never thought that the Japanese government itself played much of a role wrt the native (or imported) MAs either during the war or the postwar period; similarly in China and Indonesia. What was the Korean government doing in the first place that made competition for its support a part of the Korean MA scene, as vs. everywhere else? The Kwans would have squabbled amongst themselves the way the various ryu did in various MAs in Japan, without any government involvement, except that something extra was added to the mix. What was it?
I'm putting my money on the General, but could there be other, better explanations?