Quite frankly no one really cares what a religion teaches unless they're interested in joining. Former JW's certainly would not care, if they could simply leave their religion and join another.
What reason would their be to criticize someone's religion? We should respect and honor what our neighbors believe. We should love them and what they believe. We should not try to change or 'convert' them unless people are asking for our opinions.
We should support and pray for each other. We should take an interest in what others believe and encourage them. We should accept all people just the way God created them, - without judgment.
Thus, in a perfect world, there would be no reason for this website. There would be no reason to speak out against what the Watchtower teaches. However we don't live in a perfect world.
The reason why former JW's speak out is because they see the harm that's being done to good, kind-hearted, and God fearing people. The organization has negatively impacted millions of lives, families, and close life long friendships with no regard religious tolerance, equality, or basic human rights.