I have a question are all sticker applied parts consider used? Bricklink has
been removing these from my inventory if I listed them as new.
Yes. Applying a sticker means the sticker is Used and the part(s) on which it’s
applied is(are) Used too.
It’s like assembling parts (minifigures excluded).
“Any element with an applied sticker is considered Used. Sticker sheets missing
stickers must also be listed as Used. Individual stickers not attached to the
original sticker sheet must be listed as Custom Items.” — https://www.bricklink.com/help.asp?helpID=102
USA, California
France, Nouvelle-Aquitaine