Mormon church leaders apologized to the family of Holocaust survivor and Jewish rights advocate Simon Wiesenthal after his parents were posthumously baptized, a controversial ritual that Mormons believe allows deceased people a way to the afterlife but offends members of many other religions.If you think the Mormons are wrong about God, then what they do has no impact on you at all. So they "baptized" your ancestors. So what? If they're wrong, the worst that's happened is they wasted their time. If they're wrong, then your ancestor isn't a baptized Mormon, which should make the complainers happy.
If the Mormons are right about God, then they saved your ancestor. You may not believe in Hell, but if the Mormons are right, there is one and your ancestor was going there--but isn't now, thanks to the Mormons. And if the Mormons are right, Hell isn't going to be a place of fun and partying, so no one truly wants to go there. They did your ancestor a solid, why are you complaining?
If you're offended because you don't like it that the Mormons think your ancestor (and perhaps you) are going to Hell--you don't like the Mormons anyway, why do you care if they think you're going to Hell? You probably think their religion is kookie.
This (to my mind) strange belief of the Mormons harms no one at all and it makes Mormons feel good for doing something to help the unfortunate. In all seriousness I ask, where is the harm? I don't believe in perpetuating a medieval superstition by saying "bless you" when someone sneezes, but I don't get all bent out of shape is someone says it to me when I sneeze.