The writer's trying to argue that product managers aren't useless, but that they have too much power. Okay, sure, but they go about it in the most confusing way possible. They start off by saying that developers who think PMs are useless are missing the point, which is fair, but then they go on this whole tangent about how PMs are actually important because they can help with decision-making and project delivery..?

And then they start shitting on PMs, saying that they're not actually that smart and they only like the discovery part of their job where they get to make all the decisions. And to top it off, they say that PMs in B2B companies are useless because they're not actually talking to the people who use the product... That's literally the job of a PM, to talk to customers and figure out what they want.

And then they go on to say that if you want to innovate, you shouldn't listen to PMs, but instead put your most competent salesperson in charge of the product. That makes no sense at all.

Sadly, as someone else said, I'd assume that this article was driven by poor experiences with a PM in the past. And it's not cool to take a bash at the whole segment due to having a bad experience with someone.