They don't "single out Jews". The Mormons collect as much geneological data as they possibly can from all over the world.
Considering that everybody who believes in God will need to stick together in the battle against the secularists, what they are doing is just plain stupid.
As I noted before, I do not believe in Mormonism.
However, let's pretend for a moment that what the Mormons believe is true.
In such a world, the Mormons are trying to save as many immortal souls as possible even if they are total strangers to them. If that is what they truly believe, do you think that they would stop trying to save those immortal souls so that they can win a worldly political battle with secularists that will be of no consequence one million years from now?
The Mormons are doing exactly the same thing that Christian missionaries have been doing for centuries: Trying to save souls according to their own belief system.
If you are a devout Christian, you can see Christian missionaries as selfless individuals who are trying to help total strangers.
If you are not a Christian, you can see those same Christian missionaries as idiots who have wasted their lives away on hocus pocus that only gets a large number of natives angry at them.
Sure, seeking out names to "baptize" sounds innocent enough because they are already dead, but for one religion to claim people from other religions is tacky at the minimun, and insulting and obnoxious to the living at the worse....