I’d like to say that, in general, I agree that a post can be angry without being cruel to others, and that that seems (both superficially and concretely in a number of well-known examples) to be a good standard to attempt to achieve.
But I think the original poster is speaking to a strange catch-22; specifically that if a dominant group protects it’s privilege and the status-quo from being questioned by asserting that some standard of behavior is required, and independent of that protectionist motivation that same standard is required for separate reasons, does it support and defend the unjust protection of the dominant group’s privilege? Thus, when the issue of questioning that privilege comes up, adhering to the particular standard of behavior that defends that privilege can be counter-productive.
I think this can become particularly problematic when words or phrases are imbued with meaning beyond their initial or immediate semantics. For instance, each of these can be problematic:
“Bless your heart, you contradict point C with point D.”
This phrasing, while ‘civil’, is also subtly condescending. It is difficult to address the condescension. If you flag or remove it, it feels like ‘weak reasoning’ for doing so: the author, after all, was just using flowery language. (Indeed, some people say these sorts of things without being aware it’s condescending.) If you address it directly you move into the realm of attacking the condescending author, which immediately puts you in a disadvantageous position.
“Point C, a SJW talking point, is contradicted by B.” (Labeling in a way to associate with people who are somehow lesser)
Here, C may very well be a SJW talking point, and so this is a fact. But it’s being labelled in a way that associates the point-maker with something upon which scorn is (however inappropriately) heaped. Again, responses to this feel limited, because we’re talking ‘civilly’ about facts.
This last one might be responded to in a couple of ways, only a hairs breadth apart:
“By labelling point C a SJW talking point, you’re sinking this discussion to a deplorable level.”
“By labelling point C a SJW talking point, you’re being deplorable.”
Most people are not going to parse a difference between the two, and any moderation of this becomes dodgy at best. But both are (in my opinion) valid and angry responses. The reason I suggest they are valid is because they do not seek to be cruel, even if they do seek to ‘harm’ (in the most abstract of senses) the subject’s self-view. They are calling out shady behavior, and if that behavior is to be responded to at all, it will involve some sort of response to the earlier, ‘defensible’, baiting. Aggravatingly, this is also ‘tone policing’, because it is only addressing items adjacent to the message substance.
All of this is to say that extreme cases of profanity are easy to adjudicate. The far more insidious - and far more important to marginalized groups - issue is when language is used that aggresses at the margins: just inside the line such that it is defensible under whatever standard is set, but that makes it very hard for the other side to respond without crossing the standard’s line.
And in those cases, is appropriate to police the tone of the side bellying up to the border? Or is it appropriate to let others respond more directly to that tone, even if it weakens the ‘public park’ policy? While these questions only apply to some subset of possible discussions, many of which you can outright disallow by being particular what you will discuss, they still come up: I’ve seen it happen, for instance, in technical discussions where one party moves goal posts and another can’t really call them out without calling out that person’s specific, repeated actions.