Lori is pretty useless for the most part, but it's not like what Lori was saying to Rick wasn't true. Shane is a headcase and could wind up being danger to the group
It's really all Dale's doing though, like what someone said on talking dead about Dale and Shane, Dale knows he can't be Shane physically
so he working to turn the rest of the group against him. He already got Lori and she got Rick, if it came down to taking sides i'm sure they'd have Glenn too
Also, I still believe she'll lose the baby as a result of that wreck, otherwise what would have been the purpose of that scene?