I think the author was talking "slow" in terms of making deliberate and calculated features with long term support in mind, preserving the cohesion and integrity of what you are building.
Compared to "fast" from big tech who have 10 divisions trying hectically to invent the next big thing that can make their bosses' stakeholders rich.
I don't mind making quick decisions, but the execution should be deliberate. One of the best things of working for myself is that all-hands meetings are pretty short. I have an idea, I ask a few friends about their opinion; then, I set to work - it's simple.
But what I don't do is wreak havoc along the way. For I know, that the time to fix what I might break never comes.
Compared to "fast" from big tech who have 10 divisions trying hectically to invent the next big thing that can make their bosses' stakeholders rich.