Pierce knows who the asset is and hates Steve Rogers

Yep, more WS meta.

So based on the bank vault scene ‘but I knew him’ it’s clear to both Pierce and the technicians (and Rumlow) that the asset is Bucky Barnes, zombie best friend of Steve Rogers. And having had to put up with Steve’s stubborn ass in SHIELD for the last few years, if only indirectly, I think there is a part of him that definitely wants to break Steve. The showdown scene in Pierce’s office is part pro-forma and part exposition. Schmidt and Zola couldn’t sway Steve Rogers, he has to try.  He tries, knowing he will fail and his ego just can’t handle it.

Pierce’s ego is what drives the earlier timeline in launching the helicarriers. He’s the Red Skull for the 21st century. The bombast saved for a smaller audience.

And using Bucky is the best way to break Steve Rogers. He makes the defeat personal for the final confrontation. He wants Steve to know exactly what they’ve done to Bucky. That they’ve wiped out his best friend and turned him into an enemy. It’s a brilliant bit of mind-fuckery even if in the end it doesn’t work.