I brought it up becuase it's specifically covered in the article.
This would be a different case if A had hardcast the Therapy right before he Flashed it back. In that case, A wouldn’t have received an advantage and should be allowed to search.
At the time, I didn't realize that hardcasting Therapy right before made a difference. What my opponent did fell under this second case, and I didn't realize that it was any different from the first.
Regarding your point concerning removal: The article doesn't address it specifically, but I'd assume that if the player rewinds to handle the Rector trigger, you get back the card and Therapy goes back onto the stack. Intent is one thing, but it'd be ridiculous if forgetting a trigger allowed one to reverse the order of resolution. You should still get a window to cast Naturalize (Grip wasn't printed yet) between Bargain hitting and Therapy resolving.
Edit: Cropped out a redundant "specifically". I use that word too much.