This is a very good point and very well argued - and to some extent I agree. I believe the original author is Canadian rather than a US citizen - but that is semantic at this point. For whatever reason she is incredibly angry at white people as a collective.
As you've pointed out, there are very good reasons for this and how society handles that anger will very much inform what happens next. Is the anger justified? Absolutely. Is it helpful? I'd argue not. And that argument goes two ways.
First of all, if someone is angry and needs to express it. There are helpful and unhelpful ways to do that. If a teenager is so angry with the world that they want to take a gun and shoot up their school, they have embraced nihilism. We don't allow them to do that simply because their feelings are valid (though they often are) we attempt to find ways to offset that anger and use it productiively. In this case, the author's passion shines through but I don't think there's any real catharsis achieved in an echo chamber. What you're more likely to get with an online rant is operant conditioning by strangers. You get a dial-up response. The anger doesn't go anywhere, it keeps getting more and more radical the more it is endorsed. So yes, I agree with your pressure cooker analogy, but only if it has an adequate valve in which the pressure is released. I believe that is far more likely to be found in a therapeutic setting.
My second point is that actions in society are not divorced from the consequential actions of others. Whilst there are a selection of white liberals across North America and in Western Democracy who will endorse such things, consistently elevating the loudest and most unreasonable voices will move the voting demos to the political right. Moderates vote where they feel safest, and the left is filling up with people who take a radical and occasionally contradictory position on things like race, sex, gender, economic models and sexuality. The louder the left shouts at the centre about their lack of change and their lack of tolerance, the more vote will amass behind a right wing populist. In short... the more dangerous it will become for the very minorities these people belong to or puport to help. That's a problem - as a result it requires more people to move to the centre and bring tolerance, compassion and common sense with them.
The original article may well have been passionate, it may well have been justfiied given the historical antecedents. That doesn't make it helpful or the right approach to achieve what the author wants to achieve. Unless of course the author is continuing on a radicalised path towards nihilism, in which case the US (and by extension) Western democracies like Canada and the UK are heading for a race war.
