I think that public education, not "think of the children"-style bans, are the best thing.
Freedom of speech is a double edged sword, snail oil salespeople have the same rights as those who question them. If they don't then society becomes a tyranny of the majority.
That's 100% true of course, Free Speech applies most to the speech we despise.
On the other hand, if people are engaging in practices that are damaging people, then they need to be held to account.
Think of a Quack therapist, invoking "false memories" and hurting their patients, they need to legally be held to account, and stopped from practicing.
Or recently, the Gentle Wind Project was charged with fraud, and a bunch of other things, and put out of business.
If Landmark is factually found to be damaging people, and doing it to gain more influence over them, I think they need to be held to account.
Perhaps class-action lawsuits for damages, and things of that nature.
Bad publicity alone could drive them out of corporations. One big news expose, and no big company will touch them...
I think if things keep going as they are going, the liabilities of the damage Landmark is doing to people, is going to byte them...all it takes are a few folks who feel they have grounds against Landmark, and then get some top lawyers on contingency to pursue their class action claim.
This is why Landmark forces people to sign away their rights. But there must be a way around that.