I'm bringing it up because it's relevant because
other people do that. What you personally believe isn't relevant to this argument, because this argument of mine is about the
worst content which your proposed rules would protect. Because it WOULD protect bullying and racism and other abuse online under the label "protected opinion".
You would make it literally illegal to counteract such behavior online.
Your rule would necessarily punish Facebook for banning stalkers, punish reddit for banning racist subreddits if they're not strictly illegal, and so on.
The rule you suggest would protect their ability to harass others regardless of if that's what you intend or not. You can't just handwave away those consequences.
Can you prove that it's in fact not super trivial to circumvent bans on non hateful ideas (in non-totalitarian states)? Are here not millions of more websites besides Facebook et al? Is it not easy to go to another website?
The fact is that your proposed rule is far worse than the alternatives.
You're suggesting it's a better tradeoff to forcibly kill quality standards online so that everybody can express literally anything that's not illegal, when it's equally possible to just... Not make a law like that, and instead encourage people to go to other websites.
Each and every person should have their individual freedom to set their standards for what opinions and beliefs they approve of (the edge cases where certain collective decisions are socially harmful are covered by antidiscrimination law).
This extends also to website owners. This means that I as a forum moderator (in a different place, on reddit) has the freedom to ban others from my forum for engaging in what I consider abusive behavior. I get to decide if and when I want to take action.
The admins on Hacker News can likewise ban me from here.
Proactive intervention usually involves government censorship or police action, but can also be considered to cover blocklists and spam filters online.
Each and every one of us decides over our own "domains".
In spaces where I'm not a mod/admin (most of them, that is), "letting you" only means not reporting the account, etc.
Today's trade-off is that every person either accepts the rules for approved content that somebody else has set on their own website... Or your start your own website. Or both at once for that matter, it's trivial to visit multiple websites at once since most browsers have tabs.
If your opinion is banned in one place online, it's easy to go to another to post it. That's how the web worked since the very beginning!