Ok, let me get this straight - you build multi-million dollar temples all around the world, outfit them like a palace, and concoct elaborate "sacred" ceremonies involving special clothing, special prayers and large pools of water supporterd on life-size carved oxen.
Your church has spent many years and untold millions of dollars trying to research the geneology of every single person who ever lived
You restrict access to only the holiest, most worthy Mormon people and enlist them to be ceremonially baptized in the name of someone who has died. I understand the same live person can be proxy baptised as many as twenty times in a row, and for deceased people he or she never heard of.
By doing so, the proxy gains status within the church and with God. Indeed, unless the proxy engages in this and other "temple work", he or she CANNOT attain the highest exalation in the next life.
And all of this is because THERE IS NO BIBLICAL SOURCE THAT FORBIDS THIS!
I’m going to start a church in which we all must paint our toenails green and wear tophats. Nothin’ in the bible saying we can’t do that.