It's not the same as option 3 because nothing is being removed from the site without a specific legal requirement. There are no "bans", and any user can see all

It's not the same as option 3 because nothing is being removed from the site without a specific legal requirement. There are no "bans", and any user can see all content posted by other users if they so choose; the filtering is merely a suggestion. Option 3 involves the site removing unwanted content so that no one can see it, not just hiding it by default. As much as I personally like this option, however, I still couldn't agree with making it mandatory. Sites should be able to choose which user-contributed content they will or will not host, without being deemed liable for contributed content merely because they haven't chosen to censor it. (Frankly the idea that anyone would be subjected to legal reprisal for the content of a post—whatever it may contain—is an affront to freedom of speech and an unjust, disproportionate punishment for a victimless "crime".)