M1A2s currently in the game feature a 3x-10x zoom.
I think that this was a mistake when introducing the A2s, as the updated sight wasnt modeled in the game. The M1A1s do have a 3x-10x thermal zoom, but the A2s do not.
For example, this is the M1A1 gunner station, and you can see that the thermal zoom is indeed 3x-10x (top right part of the image)
If thats not optical zoom but digital then dont except them to add it, as digital zoom is not represented in the game, IIRC. Though if it is optical then Community Bug Reporting System
This is bug report platform you can make a bug report and have this issue fixed.