What the term covers
Scaled content abuse describes producing many pages primarily to manipulate rankings, where each page adds little or nothing the others do not. Spam policy has treated it as abuse for years, under names that have changed as the technology has.
The important part of the definition is the purpose and the aggregate effect, not the mechanism. Ten thousand pages generated overnight is the obvious case; so is ten thousand pages written by a team of writers to cover every permutation of a keyword.
The history matters because it predates generative models. Doorway pages, auto-generated city pages and scraped-content farms were all the same failure with earlier tools, and the countermeasures already exist.
So when people ask whether AI content is risky, the accurate answer is that scale without value is risky, and AI makes reaching that scale cheap.