NOTE: I’m not complaining I just want to know how this works and how best to avoid this problem.
Hypothetical - I want to respond to a post and by the time I submit it the mod has already moved the original post to another thread. (And I have yet to find the remove or delete post option. Is there one?)
As a result, my post is way out of context and the mod will have to move my post, or if nobody catches it, then all the readers don’t get what I’m saying. I’ve read several threads where there are posts that I remember from the original thread where they were originally posted but now ended up in another thread and I
Do you mean if a thread is split or just some posts are moved ? If the whole thread is moved, your post should still be in the right thread.
Sometimes I have been splitting a long thread, taking my time to decide what posts to split off (not always easy decide which posts are off topic, sometimes they wander…) And when I finally complete the procedure, someone has already added a post that belongs in the new thread because I was looking at an old version of the thread.
If that happens I have to go back and do the same with the new post, it’s the moderator’s responsability to split it properly, I don’t think there’s anything you can do better. Even if you do what you suggest it will still end up in the old thread if you do it between the mod starting the split prodecure and finishing it. But it rarely happens, so don’t worry about it. 
If you think your post is in the wrong thread, please let your friendly moderator know.