Zombies are infected. Its a question of what infects them. The infected in 28 Days later, i dont count the sequel since it was rubbish, arent undead though. They havent died and been reanimated. They simply are infected of a different kind. Hence difference in behaviour and ability. For one, they can hear, smell and see you. They also arent stronger than you due to still feeling pain unlike "proper Zombies."
So no, its not bad. Its just a different kind of Infected, which is both more human, yet still frightening. Though the underlying psychological angle of 28 Days later is what is more creepy. Because as shown at the end, uninfected humans are just as evil and "mindless" as the infected are.