I googled "IARC glyphosate" and found something that might clarify the reason for the different findings. In the IARC report, the studies they reviewed were from "17 experts from 11 countries" written by "independent experts, free from vested interests". In contrast, the EPA reviewed a database of "studies submitted to support registration of glyphosate (working for the glyphosate industry perhaps rather than independent?) and studies EPA identified in (cherry-picked from?) the open literature.
If it's so harmless, that begs the question of why the EPA set "a tolerance or limit on how much pesticide residue can legally remain on food and feed".
In any case, widespread use of it poisons bees, other pollinators, Monarch butterflies, and other insect species--some helpful and some harmful--which will lead to further degradation of the environment.