That is likely true, but doesn't really matter to this situation. The question is how long has Matt Thomas known about the deal and did he know for a fact that Hoiberg was leaving when he gave the interview. How long the deal was in the works doesn't matter, unless MT knew about it from the beginning. Even if MT did know for a fact that Hoiberg was leaving, it's still possible that Hoiberg told Thomas he was staying when he saw him in his offices after the season was over. I wouldn't doubt that because as already menitoned, people tend to lie about their true intentions in these kinds of situations.
I'm not going to bash Hoiberg on this, but I don't have any fondness or emotional attachment to him either so I'm not going to overly defend him or his character. He did what he did and I understand why he did it, but from what I've heard in the news media, I don't like how he did it. I won't be following him in his future career after what he pulled, but I won't be sending him any hate mail either.