When Rick's motley crew arrived at an abandoned rail-yard offering 'sanctuary' to all survivors, who could have guessed that things would go so wrong? Pretty much as soon as they walk through the gate they are set upon by a highly organized group of people munchers led by the charismatically creepy, Gareth.
Valued so much by the show's writers that he isn't even given a surname, Gareth nonetheless serves as an interesting antagonist. There's just no getting along with people who keep eyeing you up like a juicy rib-eye. Viewers are treated to a lot of justification for Gareth and his group's actions and even experienced exposition's best friend, a flashback, which showed that even they have gone through some pretty hard times.
Rick frequently condemns their actions stating that they are no better than the walkers, obviously Mr. Grimes and Co. wouldn't stoop to such despicable lows. Except... they totally do. As soon as they have the cannibals at their mercy, they brutally hack their defenceless, kneeling captives to death.
While he may have fulfilled his promise that the red-handled machete would have its revenge, Rick confirms pretty much everything Gareth says - the groups aren't really that different apart from their dining preferences. The church massacre reveals Rick's philosophy as revenge and murder are absolutely fine as long as you don't eat your victims. If anything, that's a waste.