I didn't get that reading at all--it seemed very much a straightforward "folks, don't be starstruck: this job is a set-up."
A story:
I was the technical cofounder (effectively) for a coworking space once upon a time. I did everything from build websites, handle mailing lists, run cable, deploy and design enterprise-class networking infrastructure, take out the garbage, and power-route through a blocked sewer drain.
It was a great job, and a good way of keeping myself in beer money while decompressing from my previous gig.
Except, at the end of the day, I wasn't a cofounder. I had no contractual stake in the company. I had no health insurance. I didn't always get payed on time. To replace me, they suddenly needed: an AV person, a networking person, a Rails developer, and somebody that could hawk their space to other developers (they were biz bros through and through, and the only developers we had at the space were basically due to my networking on their behalf).
I don't regret the time I spent there, and I still help put out fires from time to time, but it was an easy trap to fall into, and could've ended really badly for all parties involved.
In these little businesses, especially when you start taking on the technical risk, you need a stake in the company. Otherwise, you're just some schlub that was recruited to do the work.
And when the web site is updated a little late, or a power outage kills a switch because the owners cheaped out on your spec (and they will, because they think in the small), or some other damn thing, it'll be you swinging in the breeze.
And they'll shitcan you, and find the next person foolish or desperate enough to go in for it.