Questions for serious horror fans and screenwriters

I just saw this on cable and I understand the directors choice of tweaking the Bloody Mary legend but I have some questions. Besides saying her name in the mirror what did those people do to deserve to be murdered? What was the line about the apocalypse all about? Why did the living dead creatures harp on about cheating and sex? Were they trying to make a point about selfish mistakes in life being a reason for the devil to come and kill you? That this was the end of the world scenario foretold by the book of Revelations (Apocalypse)? Really? Because I know about people who do a lot worse things than cheating on their husband or having sex with a friend. Talk about a guilt trip; you deserve to be murdered because you had sex? Or did the director just forget to have a good reason for all the bloodshed. I don't get it, something is seriously missing? Could it be a good, original story?