I gave you feedback about top posting movie content before.
I think it robs the original poster of interaction. If you reached out offering change and they didn't engage you have your answer
As you said there is infinite content on the internet to import into Lemmy, no reason to steal the interactions from a small lemmy.world poster
If you must do it then it's good you used the cross post feature so there is some connection back to the original poster.
So in this scenario the lw movie poster didn't get enough engagement on their content and left... That's a net negative for Lemmy