When gun prohibitionists use the term "gun buyback," gun rights advocates laugh. "Pfft, you can't buy back something you never owned." The enemy knows this, but the use of the phrase belies their world view.
Statists think the State owns everything, and no one does anything without their permission. All rights are property rights; for the State to control everyone and everything, they must own everyone and everything. Therefore, they are not being sloppy when they say "gun buyback," it just reflects a world view where our guns belong to them anyway, and they're just letting us use them.