I dunno where you get this info from or just your own opinion, but those are incorrect.
Bluestacks is certainly legal for DL or to be precise any game from gamevil.
They have mention before on other games that they have no stance on bluestacks and as long the game apk is not modified, you are safe to play your game there.
I use bluestacks on my pc. Basically it's an android interface simulator. No different than on a phone. Apk is dled from google play and not modified. Scripts / macros or simple programmed clicking softwares are on pc so its separate from bluestacks. How you wanna run it is up to you. It cannot be detected or by tracked by DL.
