OK, this I can work with a bit more! :)
So in your first three paragraphs you are listing out more explicitly what the harms are. OK. I don't disagree with you much here. Further suggestion that we don't actually disagree as much as I thought is what you say next:
> Also, at no point did I mention suppressing the discussion.
Indeed -- strictly speaking, no you did not!
So it looks now like what you intended to convey, when you wrote that discussing such things is harmful, is that discussing such things has downsides. I.e. it is not all-upside. I'm in agreement there! I just think that the downside is so much vastly smaller than the upside.
Whereas I took you as meaning that it is net harmful; and yes, I'll admit I implicitly read in there a call to suppress such things. Given the context, I think that was a reasonable inference for me to make? That is to say, the original question this came up under related to the firing of James Damore. If you didn't intend people to infer that you meant that, I think you should have been more explicit there. Similarly you should have been more explicit that by "harmful" you merely meant "has downsides" rather than "is net harmful". (Note that "has downsides" is a very weak statement -- everything has downsides! If you've been having to argue who won't even acknowledge that discussing such things has downsides, well... sorry you've had to deal with that!)
Anyway, one way or another, while I don't think you were the most clear, we do both seem to agree that the discussion has both upsides and downsides. I'm just arguing (as I've said above) that the upside is much, much bigger than the downside.
> But you've simply turned your own argument around: you're arguing that saying "this discussion is harmful" is itself a harmful discussion!
This is why one needs to distinguish the object level from the meta level. Yes, the rules need to be different between the two. (Although, in a world where everyone understood that discussion is not to be suppressed, I wouldn't have any problem with people merely saying that discussion should be suppressed, so long as they took no action to do so!)
> And indeed we're also back to the question of whether being fired by your employer actually is a free speech question or not. There's no suggestion of government involvement in this speech, is there? Are you going to say "employees should be protected by the state from fear of being fired for any statements they make in the workplace, no matter how offensive their co-workers find them"?
...OK, I hate to say this, but this part reads like you didn't actually read my comment above. The point of free speech here, so far as I'm concerned, is to prevent the awful default human tribal positive feedback loop of posturing and wrongness. Whether the government is involved is irrelevant. What's relevant is, is this going to deter people from contradicting the consensus when they think something's wrong? Is this going to damage the negative feedback loops we need, and strengthen the positive feedback loops that have destroyed so many groups? I'd say yes, this is.
I'm not making any claims as to whether Damore should have been protected by the state! I didn't make any claims about the government at all. And honestly state protection might be helpful to Damore himself but it wouldn't do very much to alleviate the real problems in this situation anyway. It wouldn't really do very much to defuse the deterrent.
And that's what I'm concerned with here -- are the negative feedback loops that we need working? Or are we headed for unseen disaster?