Ok, so - here's a reply I got from someone when I posted this interesting piece to FB. To be clear, I am not suggesting that this article/blog post is perfect, but rather that this person's comments are really bad economics. Here's their response:

Anyway, it does have a few issues. I think just now, I've only got time to address myth one. Myth two was fine but nothing new, and myth three can be conflated with something else so a distinction needs to be made.

There are a couple issues with his figure one. First off, the way in which he's defined his areas for showing that as a percentage of GDP to the labor workforce has increased seem a little designed but with those defined regions his standard Deviation is likely to be larger or on the scale of the variation between 79% and 81%. But this is a minor point which just hints towards trying to show something which might not really be there. The major issue with his plot though is that I don't think he's adequately defined labor. He appears to have lumped all of labor together and taken the average. This hides any variation between different labor markets. Similar to why average incomes are often skewed to higher incomes than what people truly earn due to the enormity of some of the outliers this can happen to his compensation and transfer payments discussion. So, whilst for a few their share if GDP may rise through these means, this can hide the lack of or decline of other peoples transfer payments. So, I think without adequately defining the section of labor you can miss out things like this. After all, there is an enshrined minimum wage, not an enshrined dental plan, so it would be wrong to assume that every American has one. I'll add more in a bit.

Anyway, so continuation. He also discusses corperate profits as a share of GDP, pointing out that they have slightly reduced, and therefore this is a reason for us not to raise taxes on capital gains and corporate income. So, here we have an issue where he's discussing things in percentages, which I guess is OK, but it can again obscure things. One thing to question here is how many corporations are now sharing in this percentage bracket. But also to realise that over the timeframe he is discussing GDP has continued to increase at a geometric rate, so the values in pure capital are much higher. So, with this you can ask then relate it to how we do income taxes and for those there are different brackets for those earning a great deal more, and it's more easily apparent that one percentage rate for all isn't really appropriate.

R1 -

Am I losing my mind or this person basically arguing that his major contention is that the Brookings Fellow is lying or being deliberately misleading?

In a nutshell:

Myth 1 is talking about gains as between capital vs. labor (which hasn't changed much), and emphatically NOT talking about income inequality (which has increased a lot). The point is that increasing inequality is being driven by inequality within labor, not by a change in the dynamic between labor and capital as factors of production. And, because they're evaluating the myth that capital has eaten up the gains that should have gone to labor, of course they're lumping all of labor together. 'Capital' here is not a euphemism for the 1%, it is a technical concept.

In the United States, far more people get health insurance from their employer than get the minimum wage. This guys is basically dismiss empirical data because it doesn't match their prior beliefs and thus makes an incredibly bad, anti-scientific argument. When I mentioned that there are links in the article he replied that:

The references tend to lead to large data bases and it's difficult to track exactly what he did.

At which point I'm laughing to myself because he obviously doesn't get it, yet has produced several paragraphs debunking an analysis based on methods he knows nothing about.

Also, with regards corporate profits, he's quite clearly saying that, as a share of GDP, corporate profits are lower and is debunking the argument that "as a share of GDP corporate profits are at record highs, therefore we must raise capital gains and corporate tax." He explicitly states there may be other (good) reasons for raising capital gains and corporate tax, but simply that the quoted argument is technically inaccurate.

I think the best part is how this guy is trying so hard to pretend he knows what he's talking about when he's barely even read/understood the article and as if all he lacks is 'time' to address the points made.