I'm sure we're all weeping over the demise of /r/coontown and other Stormfront-affiliated subreddits. What a sad loss, and what a valuable group of users to alienate!
As far as I understand the reddit situation, a major problem is that advertisers have a strong fear of screenshots of their product next to a random badthinking redditor's screed becoming subject of some five minute hate on twitter or facebook.
If I were a US citizen, I'd be less enthusiastic than you seem to be about this situation, irrespective of coincidental alignment of (current) outcomes with personal moral sensibilities.
I'd want to look very hard at the fact that the control loop for "what you can't say" on the ad-driven internet runs through corporate ad departments and random twitter mobs.
Much as I agree that advertising as an industry needs to die (and I recommend Patreon style funding to people wanting to be immune to advertisers), in practise putting the advertisers in an armlock has often been the only way to persuade overly idealistic free-speechers to put the brakes on stalking and doxxing, child porn and the suchlike.
Sarcasm used to be a effective and totally valid way to make a point, -I mean it was even part of basic reading/writing education when I grew up 20 years ago.
Of course you can easily overdo it but I think banning sarcasm has a significant downside and we should rather teach people to use it correctly.
Once again, this isn't about banning anything. This is about productive conversation. A value which makes HN unique out of all the internet communities.
What the commenter was doing was insinuating a conclusion based upon a straw man, so as not to be scrutinised for the underlying conclusion.
I'm sure we're all weeping over the demise of /r/coontown and other Stormfront-affiliated subreddits. What a sad loss, and what a valuable group of users to alienate!