Why zoom? To get closer without having to move forward. Why compress? To save storage space on the camera.
I see, so there was no nefarious motive. Got it.
But why not film it in such a way that this crap doesn't appear? Don't they have the budget and staff for better production values than this? I'm comparing it with past press conferences of Biden's (yeah when he was in better shape) and they looked fine, no weird effects at all.
Either they were being unprofessional and sloppy, or they deliberately did this as a form of info-chaff, look, a squirrel.