Could you explain better the attack move on cursor in the client?

For months i didn't know how it worked, i even asked the support and they told me it might be a bug. I've reported it as a bug but i had no answer. Here's a video i made https://www.youtube.com/watch?v=QSL5oMPENH8.
Anyway, after a long time, i said to a friend who has been playing for a while how buggy attack move is. He told me to search on the patch notes when was it added. And then i found this:

" _NEW attack move on cursor. _ We've added a new feature, "Attack Move on Cursor," that will attempt to attack move the target nearest your cursor **if you target the ground near them. **"

This IF changes everything. Why do i have to search on a post 3 years ago to understand how it works? It went to my mind today because i've seen a bug report of somebody else who asked the same thing.

PS: I posted it here because i think adding a description in client=creation.