However, the impact of ketogenic diets (KDs), which contain even higher lipid content but reduce circulating insulin and induce ketogenesis, remains poorly understood.

I read that as saying existing science says high-fat diets that cause you to become obese increase the risk of cancer in the small intestine. Not anything about their findings in this study specifically.

The end of the abstract says:

These findings reveal that dietary lipid content, through fatty acid oxidation rather than ketone metabolism, influences intestinal tumorigenesis and highlight the need for nuanced consideration of dietary strategies for cancer prevention in genetically susceptible populations.

Which I think is implying that they found some difference between their "high-fat" (60% lard diet) and "ketogenic" (80% lard diet) cohorts.

I can't find the full content of the paper to verify exactly what they're trying to say, but I think the only claims they're trying to make are basically, 'there's no point in consuming externally synthesized ketones'. Which, yeah, but good to have proper scientific confirmation.