You're making an awful lot of assumptions. You're assuming that her reaction of anger was written into the script. You're assuming, based on facial expressions that the reaction is anger toward Rick, not anger in general. You're assuming that you know how everyone in the world would be acting during a zombie apocalypse, Then you're calling out the writers for not nailing what your assumptions amount to, in their show.
I got from the show that she was mad and disgusted and that the remark about her son 'putting Shane down' was the final straw that made her back away in horror. But those are just my impressions. To condemn the show and its writers, because they didn't live up to how a particular moment should have played out according to you, is silly. It will never be everything you hope it to be, because you aren't writing or directing it.
I think you need to re-watch the episode. If it wasn't written into the script then they sure did approve it. She broke down, and Rick tried to comfort her. She pushed him away, he tried to touch her again and she gave him that look of "Don't touch me you MFer!"
And using "you act like you know how people would act in an X scenario" as a defense? C'mon son! I think we all have a good barometer, otherwise people wouldn't write these scripts and people wouldn't watch them.
Some things work and somethings don't. Just because there's a zombie apocalypse doesn't give everyone free reign to act in all sorts of ways. In every fantasy movie, in every horror movie, a world is built and the characters grounded in that world or situation. This goes against what has been laid out.
The characters are all rational for the most part, and if they're not the motives are still somewhat understood. Writing crazy for the sake of crazy and ascribing that to Lori makes no sense in the context of the world/story they have laid out. Secondly, it's her fault.
1. She pit Rick and Shane against each other causing the whole situation.
2. She can NEVER keep track of Carl. Carl always gets into mischief, and she blames Rick. Her only job is to watch Carl.
Again, its not me. Its others in this thread, and even Chris Hardwick called them out on it. So obviously there is something that they forgot to add/mention/or do so that her reaction wasn't lost on us. That's why there's so many memes ITT about Loris character. They don't know what to do with her.
I love the show. But it's not perfect. Nothing is. That was painfully obvious to me when Dale died from a ninja zombie...