Although I don't approve of the implicit judgment. I would never walk out on a host and yell abuse because they shared their stories with me of doctors, epidurals, formula, cots and prams.
I probably wouldn't have been there in the first place!

On the flipside, my SIL punched my husband in the face because she doesn't agree with our co-sleeping, demand feeding or babywearing. Crazy that anyone can get so worked up over parenting! (I am completely guilty of doing the same thing though)

Just get out there, give love, and be awesome. We'll change their minds...