

that sounds like a magic zombie scenario and the aforementioned guidelines apply.
their dead tissue will break apart and decompose very rapidly, and dehydration will prohibit any complex movement after a few hours.
if reanimations are moving their dead bodies around without connective tissue or the fuel/cell requirements needed to work those bodily systems, that’s magic.
expecting non-magic zombies to be able to chase someone or gather in a horde is like expecting a car to run without any fuel, engine, or drivetrain.
the closest thing we have to a non-magic zombie but still similar to zombies in movies is rabies, and the person becomes violent but extremely uncoordinated, aquaphobic, and then dies because the human body doesn’t function without the constant ingestion of water and fuel sources.
there are a few big issues here.
The consistency and efficacy of that pathogen
those people wouldn’t be zombies, they would just be carnivores.
if cannibalism/societal colapse/megetables are going on, people are going to notice.
there are already pathogens that make someone vegetarian, but because of the resilience of the human body, the effect only takes hold in a very low percentage of people introduced to the pathogen (they’re not sure which mechanism in tick spit prompts the meat allergy yet, afaik).
The brain is incredibly complex and can rewire itself, so to have even 10% of the population have consistently perfectly rewired brains while maintaining all other normal functions and the coordination to conspire, cannibalize people and change the global food supply is a pretty magical scenario.