I feel like crying, "No! That's not how my personal Christianity thinks of Judaism -- and the ways in which my understanding does overlap with this one that you find offensive, let me explain how it's really not offensive."
I know that when people (who aren't even mutually friended with me) are sharing their personal pain, that that's not the time or the place for me to step in and share my alternative interpretation.
I'm still sitting with the issue (of how I should be responding in my own head -- I'm not gonna go start an argument in someone else's LJ).
Sometimes I think of Abraham
How one star he saw had been lit for me
He was a stranger in this land
And I am that, no less than he
And on this road to righteousness
Sometimes the climb can be so steep
I may falter in my steps
But never beyond Your reach