I struggle to understand why you oppose this so much. You already confirmed that they indeed leave charge pits on bridges for the exact same reason. Why don't you want to accept that these hooks serve the same purpose, but they're used when a charge pit is inconvenient - like on the support pillars in the middle?
I just got back from a 100 km trip, and I paid extra attention to this. These hooks were on every single bridge pillar I saw. There are charge pits at each end and hooks on the support pillars. It's not rebar either, but prefabricated hooks that are clearly put there for a purpose.
I'm really tempted to just email Destia and ask for a confirmation but I feel like asking stuff like that might sound a bit suspicious so I hesitate.