So maybe it does make sense for Lori to have reacted this way, having wanted to hear something else; and maybe, further, Lori has discovered what many peopele have discovered: that you can't see a person the same way when you know they've killed, especially if it was someone they knew rather than anonymous threats in an abandoned bar.
Exactly. In the dialog she almost gives Rick an "out," by asking specifically if Shane was killed by the walkers. He tells the truth. BTW his son asked the same question and he didn't lie to him either.
It probably in real life would have been smarter to tell the truth about the zombie virus when Jenner first told him but kept
the details of Shane's death to himself.
But the way they set it up creates better drama for television.