It's not about cheap. It's about ordering vs building. If you tell an architect and a bunch of workers to build you a house, even if you pick some details and make some choices, it's them that are building the house, not you.

You can feel happy about the result, you can find the house useful, but you shouldn't feel a sense of building accomplishment, because you didn't build anything.

With AI & apps there's less friction, because you don't even have to hire another human being, it's just prompting. In that sense, it's definitely closer to ordering food from an app.

In any case, in the context of TFA, there's also a sense of low quality, cheaply made. The bots making the PRs aren't reading the contribution guidelines, so that's low quality all by itself. Drowning a human reviewer with a mass of PR is also a low quality way of contributing.