She mass murdered them because they were killing the infected and she believed they should be keeping them in pins instead.
And they were going to attack Celia because the priest thinks she's somehow responsible for the whole outbreak.

At least I think. That was a confusing episode. I did a lot of reading the next day. lol

 

I think Guitarman23 has it right actually. Celia doesn't care if someone kills a random zombie, she just wants to protect the ones that were her family. The priest was saying that the zombies Celia was keeping were essentially a haven for evil and the Devil. He said that it would bring them closer to God to get rid of it. The plan was at the least to kill her zombies, but that likely would have required them to also kill Celia too.

 

The parishioners were going to attack and kill Celia and her followers because she is a witch, in a Mexican cult called "Santa Muerte" - The Holy Dead. Celia isn't keeping the walkers in the wine cellar because she is fond of them, she is keeping them in the wine cellar because she is building an army for "La Muejer Blanca" (The White Lady {of Death}) This is sort of the Santa Muerte equivalent of the Christian Rapture - except instead of the living being called to heaven, the dead are walking the earth exacting revenge on the police, the govt, the church, the powerful, etc. This is a time when the criminal, the addict, the prostitute, the poor, the wicked will rise to power and rule the earth with the help of the dead... The church isn't so much concerned about "the walkers in the wine cellar" and they are "the cult of witches" that are keeping them for their evil reign.

BTW - this is a real thing not made up for the story line.. VERY popular gang tattoo... Note the owl at her feet in the statue below...They believe owls are witches who transmute and fly during the night to do "the white lady's work". This is what the priest wanted to put a stop to and what he felt was responsible for the zombies. This is also why Salazar was so freaked out and threw the talisman overboard. This stuff scares the living crap out of observant Mexican Catholics. If my cleaning lady knew what I watched last Sunday, she would probably literally wash my TV set with Holy Water. Serious superstition at play.

 

"If my cleaning lady knew what I watched last Sunday, she would probably literally wash my TV set with Holy Water. Serious superstition at play." LOL