Since the Catholic and Mormon churches change their doctrines, isn't that proof of them being False?

All religions must change at some point as living faith is dynamic not static.As humans develop in their understanding of themselves and the universe, their spirituality advances.If correcting doctrine makes a religion false then why do protestants no longer engage in slavery,torture,killing people for committing adultery,fornication etc,etc,etc.You're also misinformed about catholics,possibly as a result of prejudice.