I am going to add a few things myself.
There currently is no relationship between ITF and WTF,
There is no formal relationship between the ITF and the WTF, this is true. There are, however, informal relationships between members of the ITF and the WTF - here, for example.
nor should there be.
I find this close-minded and self-limiting, and about as meaningful as telling a Catholic and Protestant - to use your own comparison - that they cannot, and should not, interact in any fashion solely because of their ideological differences - never mind that there's always the possibility of changing someone's mind if you are open to the ideas of others.
For if you embrace Gen. Choi's organization, you embrace his philosophy.
This is just meaningless. Exile covered this quite completely, so I won't attempt to add to his answer; I will say, however, that I was a senior color belt - possibly even a 1st Dan, before I ever heard anything about his philosophy. In the day-to-day functioning of the dojang, it is simply irrelevant.
Aside from the technical differences (ITF-sine wave, more Shotokan inspired),
Why aside from them? There are technical differences - that is well-known. Different is not necessarily bad; it is simply different. Too many people have your opinion - that "different is dead-and one death is never enouhg. You die and die and die." (Zenna Henderson,
Pilgrimage: The Book of the People). Differences should be celebrated, explored, and used to strengthen the whole - not derided and ignored.
the WTF made a concerted effort to grow and develop Tae Kwon Do according to traditional Korean thinking and philosophy. The ITF was the product of one man. The Kukkiwon/WTF is the work of many people and rooted in Korean tradition.
Interestingly enough, this is exactly what the ITF teaches... except that it teaches that Gen. Choi made a concerted effort to grow and develop Taekwon-Do according to Korean thinking and philosophy. Gen. Choi credits quite a few people with inspiring and helping him - but yes, he does take primary credit for doing much of the work... which he did, at least for his kwan. As far as the WTF being rooted in Korean tradition... well, I learned quite a bit of Korean history on my journey through TKD, and I intend to learn more - but when I started learning it, it was because it was required for promotion, to demonstrate respect for the country and culture that created the art; were ITF TKD solely for the glorification of Gen. Choi, then surely at least
one pattern (all named for persons or events significant in Korean history) would be named for him - but not one ever was. Quite a few are named for Korean patriots who worked to overthrow the Japanese - many of them contemporaries of Gen. Choi - but none for him.
Aside from his habit of taking credit for other peoples' work,
See previous.
Choi made personal overtures to North Korea, despite the fact that the North has systematically starved its own people and has a megalomaniac as a dictator.
As I said, Gen. Choi was born in a united Korea; it so happened that his birthplace was in North Korea. Is it so odd that an old man would want to return to his birthplace as his death approached?
What Choi considered patriotism, South Korea considers treason.
This is a matter of opinion. Gen. Choi was a Korean patriot, and has been painted by South Korea as less than patriotic because, due to his love for his birthplace and his desire to see his country reunited, he never gave up hope that North Korea could be turned from its Communist track and reunited with South Korea. This does not make him a traitor; it makes hima a patriot. You might check a few sources that do not originate within your own organization; history is written by the winners, and Gen. Choi did not win this fight - certainly not according to the WTF. Other sources differ in their interpretation. A
google search using the terms "Gen. Choi Hong Hi history" creates a lengthy list of sources, many of which contradict each other. Even for such recent events, history is unclear, and motivations and actions are open to interpretation.
He may have had deep affection for the region that gave birth to him, but the political reality is that his birthland was an oppressive communist country and he never faced up to that.
His birthland was a united Korea, a single, non-Communist, country, not the split country that it is today. His love was for that Korea, for the land that gave him birth, not for the Communist country that North Korea became later in his life.
And as for embracing and practicing ITF and WTF poomse, you cannot be Democrat and Republican or Catholic and Protestant. You cannot practice ITF and WTF. Each has its own nuances, philosophy, and mindset. Pick one.
Why? I would rather learn from each, and choose the best from each, than cut myself off from a large body of experience and knowledge. That is, in my opinion, censorship - something I intensely dislike and disagree with. If that is your choice, then you are welcome to choose it for yourself; for myself, I will learn from anyone who has something valuable to teach - which, in my opinion and experience, is everyone. The wheat will separate from the chaff in its own time.