Cause zoomed out you're rendering way more stuff in general(GPU load could stay constant or potentially increase).. and the cpu workload is a lot higher with 10-100x as many things on screen.
I don't think we can make any accurate judgments without more information.
Just look at the actual scene though. Watch the video. The framerate goes nuts and spikes all over and the only animations I could see @ 1080p upscaled to 1440p were the three I marked.
Do you honestly think that the graphics shown should be bringing $600 cards to their knees? I mean 4x / turn based should have the lowest hardware requirements compared to RTS / FPS.