Monsanto paid a bunch of scientists to "discover" that Glyphosate, the patented active ingredient in their RoundUp weedkiller is safe for humans, but the article was ghost-written by Monsanto employees without acknowledgement. The article claimed that Glyphosate does not cause cancer, but The World Health Organisation found that it does. Some people have trouble figuring out who is lying between the company making vast profits and the organisation tasked with keeping people healthy across the globe. RoundUp is used a LOT on genetically modified foods made by guess who to be "RoundUp ready" - resistant to RoundUp. These genetically modified foods were also found to be safe initially, but guess who funded that research who are only now, 25 years later, found to be ghost writing the articles instead of letting the scientists do their own work and draw their own conclusions.

A paper was written by a lab that received guidance and likely funding from the company whose product it was researching. Paper was published and despite red flags, it was allowed to influence 1000+ papers before it was finally redacted. Even though a correction has been made, Monsanto was still allowed to befuddle the water for so long.

ELI5: Imagine the class was asked to make a drawing of an apple, but one student that is quick and sneaky, draws an orange. The other students still learning about fruits, copy that students drawing of an orange. The teacher discovers a mistake was made, but by the time things get figured out, its too late, the assignments over and the paintings can't be undone. All that time spent on oranges.