Not sure what your point is. Pickled vegetables contain nitrosamines [1] which are definite carcinogens. It’s the same reason that processed meats are associated with increased rates of colon cancer.
Regarding caffeic acid, it’s possible that it may have different effects based on concentration and other conditions. In small doses it may be protective, in high doses it may be carcinogenic. From the Wikipedia article:
“ Some studies have shown that it inhibits carcinogenesis, and other experiments show carcinogenic effects.[22] Oral administration of high doses of caffeic acid in rats has caused stomach papillomas.[22]“
Aspartame is interesting in that unlike caffeic acid, it's a newly-introduced substance that saw rapid, widespread adoption in the mass market. So, where's the statistical increase in cancer rates among aspartame consumers that would have accompanied such a trend, if aspartame were carcinogenic to humans? Is there one? No? Well, what made them even ask the question, then?
When everything causes cancer, nothing does. Like Proposition 65, actions like this ultimately leave us all less aware, less informed, and less safe.
One issue in cancer stats is the frequent misattribution of cancers to smoking.
You smoked for 4 years 20 years ago? Then that's what is put as the "cause" for damn near any cancer, which totally destroys the value of the stats.
What we can see though is that rates have generally gone up, either due to increased detection or due to actualized rate increases (most likely a combination of both).
Regarding caffeic acid, it’s possible that it may have different effects based on concentration and other conditions. In small doses it may be protective, in high doses it may be carcinogenic. From the Wikipedia article:
“ Some studies have shown that it inhibits carcinogenesis, and other experiments show carcinogenic effects.[22] Oral administration of high doses of caffeic acid in rats has caused stomach papillomas.[22]“
[1] https://pubmed.ncbi.nlm.nih.gov/1831733/