As noted in their other reply, it is actually not a typo. A central part of their point is in that first sentence they note the extra eyes on marginalized people making more money than other marginalized people, but it’s blown out to being extremely exaggerated.
So yes, I think there is a “grave epistemic problem” with the first sentence that hurts the argument and its credibility as a whole, without having to get into the details of the argument itself.
That you called the first replier “stupid” or even their argument “stupid” is wholly unjustified.
Orders of magnitude are typically in log 10, 2^2 being 4 is in the same order of magnitude.
The national average wage for the USA is roughly 70k according to a quick Google search, unless you’re suggesting the devs are making $4.9 billion per year I think you’re not using exponents correctly.
I don’t think it’s unfair to call out the first sentence of the argument, if you’re trying to persuade with several paragraphs of content and the very first sentence has a gross error, it transcends pedantry in my opinion.
Rather, I think it makes the original argument look irrational if they have an extreme exaggeration if they have to use that to make their point.