The zombies of 28 Days Later and its sequel 28 Weeks Later can run at incredible speeds and are highly attuned to their surroundings, making them a far scarier enemy than any typical movie zombie.
The ban was prompted by a viral tweet that cautioned anyone who hates jump scares or had anxiety to look away and turn down the volume when they saw an ad & with the volume being turned down and nothing else. The ad in question is clearly designed to freak out the viewer as much as possible.