Grandmas can be growing it in heavily contaminated soils (old motor oil, lead, arsenic, etc.), or using ‘random weed spray’ at 10x its recommended dosage, or not washing their hands after using the toilet and then handling veggies, etc.

The idea that Roundup is the worst pesticide being used is optimistic.

It’s like the GP indicates - I think the concern is more for yield than safety.

My experience as a tourist was that some fruit reeked so strongly of chemicals that I just kept away from it.

Your scenario provides far fewer applications of pesticides than the alternatives, especially those in "organic farming", with a pesticide that is much less bad than the common alternatives.