If you take your faith seriously I don't think you can get upset with other people taking their faith (or lack thereof) seriously. I don't agree with Wiesel on everything but once someone's gone leave them be. I would probably be upset too if I discovered someone else was claiming anything posthumously about loved ones.
What you're saying doesn't make much sense to me. It's like the self-proclaimed atheists who can never stop ranting on and on about how there
isn't a God. They spend so much time and energy about something they profess to not even believe in.
If we Mormons are full of crap, than us doing proxy-baptisms for the deceased in our temples doesn't have
ANY impact on
ANYONE whatsoever. We're just going through the motions.
If some other church/religion deciding to start doing baptisms for the dead tomorrow, and wanted to do it for my great grandfather, I wouldn't think anything of it because I don't believe what they're doing has any efficacy anyway.