Ok. Tracy Kenpo has adopted Tai Chi Chuan into the curriculum. The history of how and when that happened, and from whom they learned is something that I do not know. I read that article, and to be honest, I often have trouble keeping all the names of old, dead Chinese masters straight in my head, so it just doesn't sink in.
I have not learned Tai Chi in the kenpo curriculum, so I cannot make any comment nor judgement on what is being taught. I have learned tai chi from a Chinese-American Sifu, so that is my frame of reference, altho the bulk of my training has been in Chen style, with very little in Yang.
This particular article belongs to Will Tracy, one of the three brothers. Will has, I believe, mostly separated from the Tracy Kenpo organization, which is headed by Al Tracy. I believe there is still some connection between them (they are brothers, after all), but it is my understanding that Will is not any kind of official spokesperson for Tracy Kenpo.
Now, I cannot comment on Will's experience with tai chi. I wasn't there, I certainly don't know his teachers, nor have I ever met Will himself, to experience that which he writes about. So take it for what it is: it's his perspective on things (much like we ourselvesl have about just about everything). Maybe he's right, maybe he's wrong, I don't know and I don't care. He was one of the very early participants in kenpo having studied with Mr. Parker in th 1950s and having received his Shodan from William Chow. A lot of people don't like what he has to say about things, especially where Mr. Parker is concerned. That's fine, it's just his perspective. If you find that his writings bug ya, then don't read them. If you chose to read them, take them with as much salt as you feel is appropriate.
Will Tracy's writings have been discussed at length here on MT. I hope this doesn't go down that road again, 'cause it ain't worth it.
But to get back on topic, yes, Tai Chi Chuan is part of Tracy Kenpo. If/when I learn that aspect of our art, it will be interesting for me to compare and contrast it to the tai chi that I already practice.