But at the same time I believe the damage this cult inflicts on families would susprise the average person.
I wonder, if you took a random sampling of 8 million people, if they would come out "ahead" by comparison with the 8 million JWs?
Yes, the WTS undoubtedly does things wrong and causes harm. I'm definitely not trying to say they don't. I have personally been impacted by their teachings. But when weighing things up you have to be fair and I think this makes valid criticism more powerful when you are. They also tend to be fairly clean living and law abiding so it's swings and roundabouts to some extent and I wonder how many people who have dysfunctional families that they blame the WTS for would have had dysfunctional families anyway (and some that would have had them don't).
It's impossible to play "what if" for large groups of people. We can only compare per-capita stats for the group with other groups and I don't remember seeing any damning evidence in this regard and we'll probably never know because the statistics are practically impossible to come by.
People have their own agency and too often the WTS is blamed for everything as a way of offloading personal responsibility for choices they have made. Is someone who refuses to vaccinate their child to blame for them falling ill or the person who pushed some quack science? If the latter, do you consider the parent has any responsibility whatsoever and what is the solution if they didn't? Should there be a government agency telling us all how to live our lives?
We live in a free society and that freedom includes the right and opportunity for people to make bad choices, follow poor leaders and believe in stupid things that will hurt or harm them. Even as someone who has been hurt by them, I'd rather live with those freedoms than give them up for the illusion that some government agency headed by an election-chasing politician is going to take better care of my life and make good choices for me.
The one thing secular authorities could do is to teach critical thinking in schools and universities so people learn how to identify lies, learn the shaky ground that religion is based on and learn to take control of their own lives. It's unlikely ... because politics is so like religion, it relies on stupid believers and the powers-that-be want to keep it that way.